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Limited research considers the ethnic and cultural diversity among the US Black population, and how this diversity influences diet. The purpose of the present qualitative study is to (1) explore the influence of culture, nativity and ethnicity on the diet of US-born, African-born and Caribbean/Latin American-born Blacks and (2) explore a model of dietary acculturation among the African-born and Caribbean/Latin American-born Blacks. The purposive sample included twenty-two US-born, fifteen Caribbean/Latin American-born and ten African-born Blacks (n 47) living in Boston, who participated in either an in-depth interview (n 12) or a focus group (five groups, size 5–9). Satia-Abouta's model of dietary acculturation informed the interview and focus group questions, which explored the influence of psychosocial factors, taste preferences and environmental factors on dietary changes. NVivo 10 software was utilised for the coding and analysis. Topics based on a priori and posteriori analyses included differences in psychosocial factors and taste preferences and environmental factors by nativity. Caribbean/Latin American-born and African-born Blacks expressed the importance of cultural identity in their dietary preferences and found adaptive strategies to maintain cultural diet, while US-born Blacks demonstrated a variety of preferences for traditionally African American foods. Environmental factors varied by place of birth and residence, with US-born Blacks citing poorer quality and limited affordability of foods. These findings suggest the importance of psychosocial and environmental factors in shaping the diet of the ethnically diverse US Black population and underscore the dietary diversity within and across the different ethnic groups of Blacks.

Cell lines were established in vitro from five peritoneal mesotheliomas produced in rats by the injection of crocidolite asbestos. These tumours exhibited the previously described diverse range of histological patterns normally associated with mesotheliomas. This diversity of appearance was also evident in culture but cell patterns in vitro did not necessarily correspond to the histology of the original tumour. With increased time in culture most cell lines tended towards a pattern of random orientation associated with the piling up of cells to form discrete masses. Despite this variation in cell pattern in culture, few ultrastructural differences were seen during electron microscope examination. Following varying periods in culture, some cell lines from these tumours were injected into either rats or athymic mice. Only one typical rat mesothelioma was produced but all cell lines produced tumours in athymic mice. The implications of these findings are discussed in relation to the aetiology of asbestos induced mesotheliomas.

Rats were exposed by inhalation to coal mine dust, titanium dioxide, or quartz. The magnitude of the consequent inflammatory response was assessed by counting numbers and types of leukocytes in the bronchoalveolar lavage fluid. The magnitude of the inflammatory response reflected the toxicity of the dusts, with quartz eliciting the greatest recruitment of inflammatory leukocytes, coal mine dust less than quartz, and titanium dioxide eliciting no inflammation. To assess the persistence of the inflammation, groups of rats were maintained in room air for 30 or 60 days after cessation of dust exposure and then numbers of leukocytes were assessed. Bronchoalveolar leukocytes in rats exposed to coal mine dust were reduced after exposure, but in the quartz-exposed rats the numbers increased with time after exposure. The chemotactic responses of bronchoalveolar leukocytes from rats inhaling coal mine dust and quartz were reduced and remained so after a 30-day recovery period. Their reduced ability to chemotact did not fully prevent macrophages from leaving the bronchoalveolar region of dust-exposed rats. However, it is likely that the delayed removal of inflammatory leukocytes with the potential to injure the lung tissue may contribute to septal damage and so contribute to the pathogenesis of pneumoconiosis.

We have previously reported that normal pleural leukocytes secrete a urokinase-type plasminogen activator inhibitor (PAI) in culture. In view of the pathogenic effects of asbestos on the pleura, in particular pleural fibrosis, we have extended these observations to crocidolite asbestos-exposed rats. Pleural leukocytes from rats exposed to crocidolite asbestos were found to secrete more PAI in culture than controls. The activity of PAI in pleural leukocyte-conditioned medium increased in a dose-dependent manner in relation to the quantity of asbestos injected into the lung. However, with increasing time post asbestos instillation, there was no significant change in the secretion of PAI by pleural leukocytes in culture compared with earlier time points of crocidolite-exposed rats. Plasminogen activator was not detectable in the conditioned medium at any time point. The data derived from this study may help to elucidate the pathogenesis of some pleural disorders caused by exposure to fibrous dusts in the lungs.

This study assessed the potential harmfulness of particles in the lung by measuring their ability to elicit and maintain an inflammatory response and to damage lung tissue. It compared the inflammogenicity of two nondurable, biological particulates (Corynebacterium parvum and zymosan) with a pathogenic mineral dust (quartz) and a nonpathogenic dust (titanium dioxide) by dosing rats via the intratracheal route and measuring the consequent alveolitis. The magnitude and duration of the inflammatory response were assessed by measuring the total number of leucocytes and the percentage of neutrophils obtained by bronchoalveolar lavage. Two key functional parameters of the lavaged leucocytes--ability to degrade fibronectin and production of plasminogen activator--were also measured. A marked inflammatory response had occurred by one day after instillation, characterised by increases in total leucocyte numbers and percentage of neutrophils in the bronchoalveolar lavages, with all four test materials. In all but the quartz exposed animals, the inflammation subsided rapidly thereafter, approaching control levels by 15 days after injection; in the quartz exposed animals the alveolitis persisted for up to 30 days. All of the inflammogens generated chemotaxins in rat serum in vitro and so, by analogy, might also be expected to generate chemotactic activity in alveolar lining fluid which could contribute to the generation of an inflammatory response. The cellular inflammatory response was accompanied by a concomitant increase in the proteolytic activity of the bronchoalveolar lavage leucocytes but production of plasminogen activator remained unchanged. In vitro exposure to the inflammogens had no effect on the proteolytic activity against fibronectin or on the plasminogen activator activity of bronchoalveolar leucocytes.

Rats were exposed to clouds of the following pneumoconiotic dusts: quartz, coal-mine dust, and chrysotile asbestos at 10 or 50 mg/m3 for 8, 32, and 75 days; for comparison, rats were also exposed to the non-pathogenic dust titanium dioxide (TiO2). The bronchoalveolar leukocytes (macrophages and neutrophils) from dust-exposed and control rats were obtained by lavage and tested for their ability to migrate toward zymosan-activated serum. Varying amounts of neutrophils were present depending on the ability of the dust to cause inflammation and the length of exposure. There was a marked loss of chemotactic ability in leukocytes from rats inhaling the pneumoconiotic dusts compared with controls; TiO2-exposed leukocytes had some impairment of chemotaxis, but this was substantially less than that found with the pneumoconiotic dusts. The loss of chemotactic activity did not correlate with the percentage of neutrophils in the lavage cells except when there were very high levels of neutrophils, and there was substantial impairment of chemotaxis with negligible numbers of neutrophils, showing that macrophage chemotaxis was impaired. A phagocytic burden within the leucocytes was not sufficient alone to inhibit chemotaxis, nor was the loss of chemotactic activity due to occupied receptors, since incubation failed to restore chemotaxis. Loss to chemotactic activity by leukocytes from pneumoconiotic dust-exposed lung could be an important factor in the development of pneumoconiosis.

Four separate experiments were carried out to investigate the effect of extremely low frequency magnetic field (MF) exposure (60 Hz, 1 mT rms) on urinary 6-sulphatoxymelatonin (aMT6s) levels in Sprague-Dawley rats. In the first experiment, immature male rats maintained under a regular 12 h daily photoperiod (white fluorescent light) were exposed to a 20 h daily MF exposure for 6 weeks. The second experiment was similar to the first, except that the MF exposure was limited to 10 days. In the third experiment, adult male rats acclimated to a combination of continuous dim red light and regular 12 h daily photoperiod (white fluorescent) were subjected to a single 1 h exposure to intermittent MF (1 min on and 1 min off cycles), 2 h before fluorescent lights went off. The fourth experiment was similar to the third, except that the animals received 2 consecutive days of 20 h daily exposure to intermittent MF, beginning 1 h before the fluorescent lights went off each day. In all four experiments, the circadian profile of urinary aMT6s was examined before, during, and after the MF exposure. No significant effect of 1 mT MF on indoleamine metabolism was observed in any of the above experiments. However, in one of the experiments (no. 4), both the control and the MF groups showed a lower aMT6s level during the exposure days, when compared with that of pre- and post-exposure days, suggesting that the existence of possible effects with lower field strengths at the range of stray field cannot be ruled out.

The pineal hormone, melatonin, plays an important role in the regulation of diurnal and seasonal rhythms in animals. In addition to the well established actions on the brain, the possibility of a direct melatonin action on the spinal cord has to be considered. In our laboratory, we have obtained data suggesting that melatonin receptors are present in the spinal cords of birds and mammals. Using radioreceptor binding and quantitative autoradiography assays with 2-[125I]iodomelatonin as the specific melatonin agonist, melatonin binding sites have been demonstrated in the rabbit and chicken spinal cords. These sites are saturable, reversible, specific, guanosine nucleotide-sensitive, of picomolar affinity and femtomolar density. The linearity of Scatchard plots of saturation data and the unity of Hill coefficients indicate that a single class of melatonin binding sites is present in the spinal cord membranes studied. The picomolar affinity of these sites is in line with the circulating levels of melatonin in these animals suggesting that these sites are physiologically relevant. Autoradiography studies in the rabbit spinal cord show that melatonin binding sites are localized in the central gray substance (lamina X). In the chicken spinal cord, these binding sites are localized in dorsal gray horns (laminae I-V) and lamina X. As lamina X and laminae I-II have similar functions, melatonin may have comparable roles in the chicken and rabbit spinal cords. Moreover, in the chicken spinal cord, the density of 2-[125I]iodomelatonin binding in the lumbar segment was significantly higher than those of the cervical and thoracic segments. The densities of these binding sites changed with environmental manipulations. When chickens were adapted to a 12L/12D photoperiod and sacrificed at mid-light and mid-dark, there was a significant diurnal variation in the density (maximum number of binding sites; Bmax) of melatonin binding sites in the spinal cord. After constant light treatment or pinealectomy, the Bmax of melatonin receptors in the chicken spinal cord increased significantly in the subjective mid-dark period. Moreover, there was an age-related decrease in the 2-[125I]iodomelatonin binding to the chicken spinal cord. Our results suggest that melatonin receptors in the chicken spinal cord are regulated by environmental lighting and change with development. These receptors may play an important role in the chronobiology of spinal cord function. The biological responses of melatonin on spinal cords have also been demonstrated in vitro. Melatonin decreased the forskolin-stimulated cAMP production in the chicken spinal cord explant. Preincubation with pertussis toxin blocked the melatonin effect. Our results suggest that melatonin receptors in the chicken spinal cord are linked to the adenylate cyclase via a pertussis toxin-sensitive G protein and that melatonin binding sites in spinal cords are melatonin receptors with biological functions. These receptors may be involved in the regulation of spinal cord functions related to sensory transmission, visceral reflexes and autonomic activities.

The pineal hormone melatonin controls circadian behavior of a variety of organs in different species, including humans. However, the precise mechanism (or mechanisms) by which this occurs remains largely unknown. At the cellular level its effects are believed to be mediated via interaction with specific melatonin receptors (MR), which have previously been cloned from human brain (Mel1a) and retina (Mel1b). At the tissue level, MR have been investigated primarily through empirical definition of specific binding sites, but so far there has been little success in biochemical or molecular characterization of native MR. In the kidney, there is strong circumstantial evidence that melatonin affects diurnal variations in renal function, but relatively little is known about the overall glomerular vs. tubular contributions to these effects. The strategy behind the present study was to use a panel of peptide-specific antibodies to identify MR proteins in various tissues, and from a determination of the intrarenal distribution of MR, gain insight into the mechanism by which melatonin might regulate kidney function. We used two peptide-specific antibodies directed against different regions of Mel1a to identify MR. Our results show that the native Mel1a receptor is a 37 kilodalton (kDa) protein in human and rat brain. Further, immunofluorescent studies carried out in guinea pig kidney have revealed that anti-Mel1a antibody is also localized to the basolateral membrane (BLM) of the renal cortical epithelium, especially the early proximal tubule. Immunoblotting of purified BLM fractions from guinea pig renal cortex and small intestine using the two different peptide-specific antibodies reveals the presence of a single peptide-blockable band at 37 kDa. These same BLM fractions also demonstrate the presence of high-affinity 2-[125I]iodomelatonin (125I-MEL) binding sites, with the pharmacological specificity of binding expected of the Mel1a receptor subtype, inhibited by guanosine 5'-O-(3'-thiotriphosphate) (GTPgammaS) and pertussis toxin. We conclude that functional MR in guinea pig kidney and small intestine are of the Mel1a subtype, and are expressed as 37 kDa proteins localized to the BLM and coupled to a pertussis toxin-sensitive G-protein (Gi). This localization strongly suggests that the proximal tubule plays a significant role in mediating the renal action of melatonin.

EST 221 derived from human adult testis detects homology to the Drosophila fat facets gene (fat) and has related sequences on both the X and Y chromosomes mapping to Xp11.4 and Yq11.2 respectively. These two loci have been termed DFFRX and DFFRY for Drosophila fat facets related X and Y. The major transcript detected by EST 221 is-8 kb in size and is expressed widely in a range of 16 human adult tissues. RT-PCR analysis of 13 different human embryonic tissues with primers specific for the X and Y sequences demonstrates that both loci are expressed in developing tissues and quantitative RT-PCR of lymphoblastoid cell lines carrying different numbers of X chromosomes reveals that the X-linked gene escapes X-inactivation. The amino acid sequence (2547 residues) of the complete open reading frame of the X gene has 44% identity and 88% similarity to the Drosophila sequence and contains the conserved Cys and His domains characteristic of deubiquitinating enzymes, suggesting its biochemical function may be the hydrolysis of ubiquitin from protein-ubiquitin conjugates. The requirement of faf for normal oocyte development in Drosophila combined with the map location and escape from X-inactivation of DFFRX raises the possibility that the human homologue plays a role in the defects of oocyte proliferation and subsequent gonadal degeneration found in Turner syndrome.

We have compared the pharmacological characteristics of 2-[125I]iodomelatonin binding to crude membrane preparations of the lung, spleen, brain and kidney of chicken. Saturation studies indicated significant differences (p0.05) in the equilibrium dissociation constant (Kd) and maximum number of binding site (Bmax) values among the four tissues studied. The descending order of affinities was lung = spleenbrainkidney. Competition curves of 2-[125I]iodomelatonin binding to crude membrane preparations of all four chicken tissues by melatonin were studied simultaneously to reduce individual, physiological, age and interassay variations. Similar competition experiments were also performed on 2-phenylmelatonin, 2-iodomelatonin, 6-chloromelatonin, 6-hydroxymelatonin and N-acetylserotonin (NAS). Concentrations of indoles which inhibited 50% of specific 2-[125I]iodomelatonin binding (IC50) were calculated. The IC50 of 2-[125I]iodomelatonin inhibition curves by the indole compounds in different tissues showed the following descending orders of affinity: (1) melatonin: lung = spleenbrainkidney, (2) 2-phenylmelatonin: lung = spleen = brain = kidney, (3) 2-iodomelatonin: lung = spleen = kidneybrain, (4) 6-chloromelatonin: lung = spleen = kidneybrain, (5) 6-hydroxymelatonin: kidneylung = spleen = brain, and (6) NAS: kidneylung = spleenbrain. The non-hydrolizable GTP analog, guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), exhibited differential effects on the saturable binding of the four tissues. GTP gamma S increased the Kd of 2-[125I]iodomelatonin binding by 2- to 3-fold in the lung and spleen, 0.5-fold in the brain and 1-fold in the kidney. Based on our findings, we would like to suggest that the 2-[125I]iodomelatonin binding sites in these four tissues may belong to three different high affinity (picomolar) subtypes of melatonin receptor. We name them cML1A represented by the lung and spleen, cML1B by the brain and cML1C by the kidney.

[125I]-Labelled iodomelatonin binding to brain membrane preparations was examined in adults of 4 species of salmonid fishes; 3 species were of cultured stock (Arctic charr, Atlantic salmon, rainbow trout) and 1 was taken from the wild (coho salmon). The specific binding of 2-[125I]iodomelatonin to the brain membrane preparations collected from all 4 species was specific, stable, saturable, reversible and of high affinity. Competitive inhibition studies showed that only melatonin, 2-iodomelatonin, 6-chloromelatonin and N-acetylserotonin showed significant inhibition of radioligand binding. In the 4 species studied, the equilibrium dissociation constant (Kd) ranged from 9.3 +/- 0.2 pmol/l in coho salmon to 13.2 +/- 0.7 pmol/l in rainbow trout, and those in rainbow trout were significantly higher (p0.05) than in the others. The maximum number of binding sites (Bmax) of the Atlantic salmon preparations (14.3 +/- 0.7 fmol/mg protein) was significantly higher than those of the other 3 species (means ranging from 9.9 to 11.6 fmol/mg protein). Hill coefficients of all 4 species were close to unity indicating one class of binding site. The interspecies differences in Kd and Bmax could not be correlated with phylogeny or life history of the various species. For the three cultured species, samples were collected at both mid-dark and mid-light to examine for diurnal variations; none were found.

The existence of melatonin receptors in adrenal glands is suggested by effects on rodent adrenal function which follow pinealectomy or in vivo and in vitro melatonin treatment. In 1992, Persengiev and coworkers reported specific binding of 2-[125I]iodomelatonin to rat adrenal tissue. In order to study adrenal binding further we have done binding studies on adrenal membranes from ducks sacrificed at midlight. We observed binding of 2-[125I]iodomelatonin which was specific, rapid, saturable, stable, reversible and of high affinity. Scatchard plots were linear and Hill coefficients were close to unity supporting the existence of a single class of 2-[125I]iodomelatonin binding sites. On Scatchard analysis the Kd was in the physiological range (27.4 pmol/l) together with a Bmax of 3.38 fmol/mg protein. Sites were highly specific to melatonin and its two synthetic analogs, 2-iodomelatonin and 6-chloromelatonin in pharmacological studies. In autoradiographic studies on the chicken adrenal gland, one class of 2-[125I]iodomelatonin binding site was demonstrated with a Kd of 58.8 pmol/l and Bmax of 182 fmol/g tissue. Kinetic and pharmacological studies indicated that these sites are saturable, reversible, and of high specificity and affinity. These findings in the chicken are similar to those of the duck adrenal data obtained by radioreceptor assay. In preliminary studies, no significant difference was found between 2-[125I]iodomelatonin binding to the adrenal glands collected at midlight and middark. These high-affinity binding sites are similar to those reported in a wide variety of tissues and are consistent with the hypothesis of direct action of melatonin on the adrenal gland.(ABSTRACT TRUNCATED AT 250 WORDS)

We describe a solid-phase competitive enzyme immunoassay for determination of melatonin in serum. The detection limit of the assay is 1.0 fmol/well. Low cross-reactivity of the antiserum with other indoles, parallel serum extract dilution and melatonin standard curves, good analytical recovery, and within- and between-assay CVs of 6.4-14.4% provide validation of the assay. Linear regression analysis of melatonin concentrations measured with this assay (y) and with a commercial 3H RIA (x) in 88 sera yielded the relation y = 0.62 x - 0.76, Sy/x = 0.03. Values for melatonin in serum samples from healthy subjects are lower during the day than during the night. Melatonin response in rat serum and pineal gland to isoproterenol injection is similar to published RIA data. The analytical procedure is also simple. Thus, the assay should have practical applications in investigation of pineal function in both clinical and basic studies.

The pineal gland plays an important role in seasonal adaptation including variation in energy requirement. Animals exhibiting seasonal changes in their energy expenditure would be benefited if their cardiac and pulmonary systems respond to the pineal photoperiodic signal, melatonin, appropriately. Thus, we would like to hypothesize that melatonin receptors are present in the heart and lung. Using a specific labeled melatonin agonist, 2-[125I]iodomelatonin, binding sites were demonstrated in the lung and heart of birds and other animals. In the chicken lung, there were high affinity (equilibrium dissociation constant, Kd = 9.11 +/- 0.73 pmol/l) and low density (maximum number of binding sites, Bmax = 1.29 +/- 0.16 fmol/mg protein) 2-[125I]iodomelatonin binding sites that were highly specific to melatonin. Similar binding with lower density was demonstrated in the quail and frog lungs. In the duck heart, specific 2-[125I]iodomelatonin binding sites with a Kd of 30.5 +/- 3.5 pmol/l and a Bmax of 0.46 +/- 0.1 fmol/mg protein (n = 4) were demonstrated. Competitive studies suggested that these binding sites were specific to melatonin. Thus, saturable and reversible 2-[125I]iodomelatonin binding was present in the lung and heart membrane preparations of birds and possibly other animals. The picomolar affinity, femtomolar density and highly specific pharmacological profile of these binding sites suggest that they can be classified as ML-1 melatonin receptors. The 2-[125I]iodomelatonin binding sites described in the lung and heart as well as those binding sites demonstrated in other peripheral tissues suggest the ubiquitous direct action of melatonin on peripheral tissues.

The affinities and densities of 2-[125I]iodomelatonin binding sites in the brains and gonads of male Japanese quail following short photoperiod treatment were studied. At 6 weeks old, control quail were placed under a 14 hour light/10 hour dark photo-stimulatory cycle and experimental quail were housed under a 7 hour light/17 hour dark photo-inhibitory lighting regime. Eighteen weeks after photic manipulation, the birds were killed at mid-light. The photo-inhibited quail had very small testes. Brains and testes of control and experimental quail were collected for receptor binding studies. The maximum number of binding sites (Bmax) of 2-[125I]iodomelatonin determined by saturation studies and the number of 2-[125I]iodomelatonin binding sites determined by a one-point binding assay in the testes of short-day quail were significantly lower (p0.05) than those of the testes in reproductively active birds kept under long photoperiod. There was no significant difference (p0.05) between the testicular Kd (equilibrium dissociation constant) values of these two groups. As for the Kd and Bmax of 2-[125I]iodomelatonin binding sites in the whole brain, there were no significant differences (p0.05) between the two groups. The higher level of testicular 2-[125I]iodomelatonin binding sites in photostimulated birds may be related to an up-regulation of melatonin receptors by the suppressed pineal melatonin secretion under long photoperiod. The lower testicular 2-[125I]iodomelatonin binding sites under short photoperiod may be the result of down-regulation of melatonin receptors by the stimulated melatonin pattern in the photo-inhibited birds.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the pleural leucocyte response to severe alveolar inflammation, heat-killed Corynebacterium parvum were instilled intratracheally into the lungs of PVG rats and pleural lavage was performed. Polymorphonuclear neutrophils are not normally resident in the pleural space but were found transiently after intratracheal instillation of C. parvum. Macrophages increased gradually in the pleural space following instillation, reaching a peak at day 5. The activity of plasminogen activator inhibitor in the pleural leucocyte supernatants was increased at day 1, but returned to control levels by day 5. The activities of interleukin-1 and tumour necrosis factor secreted by pleural leucocytes were decreased compared with control pleural leucocytes at day 1 and were further reduced at day 5. The analysis of particle translocation showed that intratracheally instilled C. parvum and fluorescent beads with or without C. parvum did not reach the pleural space. We hypothesize that pleural inflammation resulting from C. parvum-induced inflammation in the lung is the result of transfer of a diffusible factor from the adjacent parenchyma.

The bronchoalveolar leukocytes from quartz-inflamed lung were separated into macrophage-enriched and neutrophil-enriched populations on density gradients. Neutrophil-enriched populations showed the greatest activity in causing injury to epithelial cells and fibronectin in vitro. Inflammatory macrophage-enriched populations from quartz-exposed lung had the ability to cause fibronectin degradation but could not cause detachment injury to epithelial cells over and above that caused by control alveolar macrophages. Fibronectin damage in vivo could be an important factor in disordering the connective tissue scaffold of the lung, thereby favoring fibrosis. In vitro quartz stimulated more production of cytokines by alveolar macrophages than the inert particulate titanium dioxide. Cytokines could be important in upregulating adhesion molecules in the membranes of lung cells in vivo; this process could aid leukocyte/lung cell contact, allowing epithelial injury to be expressed, and could also be a factor leading to pathological change.

Both epithelial injury and inflammation are characteristic findings in the centriacinar regions of the lungs of rats exposed to ozone. In humans such effects could lead to long-term lung damage and disease. In animals, neoplastic change in the lungs after exposure to ozone has been described previously. The possible relationships between inflammatory cell recruitment, epithelial injury, and hyperplasia, with special regard to the important role of repair processes in leading to increased incidence of tumors in some species, have been addressed in the present study. We have previously described that leukocytes from lungs inflamed by different agents can injure epithelial cells in vitro. We have suggested that this leukocyte-mediated epithelial injury could enhance epithelial turnover in ozone-exposed lungs and so enhance the likelihood of tumor development. We, therefore, set out to test the hypothesis that bronchoalveolar leukocytes from ozone-exposed lungs can injure epithelial cells in vitro. PVG rats were exposed to 0.2, 0.4, 0.6, and 0.8 parts per million2 (ppm) ozone for seven hours per day for up to four days. On the morning following the last exposure, bronchoalveolar lavage was used to sample the bronchoalveolar leukocytes and the following parameters were assessed: total number, differential leukocyte count, production of oxidants, ability to degrade fibronectin, and ability to injure epithelial cells. In addition to these parameters, which were measured at all concentrations and time points in limited experiments, we also assessed macrophage size in short-term culture and inflammation in histological sections of lungs. Total number of lavageable cells was not affected by ozone inhalation. However, the percentage of macrophages decreased with ozone treatment and the percentage of neutrophils increased on days 1 and 2 at 0.6 and 0.8 ppm ozone. There was no significant effect of ozone exposure on the ability of neutrophils to degrade fibronectin or injure epithelial cells. Production of superoxide anion in response to stimulation with phorbol myristate acetate was significantly decreased by exposure to 0.6 ppm ozone, as described in previous studies. Macrophages from the lungs of rats exposed to ozone were larger than control macrophages.

Leucocyte proteinases are considered to be central to the tissue damage that is associated with chronic inflammatory lung disease. Both acid and neutral proteinases have the ability to degrade connective tissue molecules and both may therefore play a part in tissue proteolysis in inflamed lungs. In this study we have used a rat model of lung inflammation to investigate levels of acid and neutral proteinase activity in the bronchoalveolar region of control and inflamed lungs. We assessed the ability of proteinases, secreted by resident and inflammatory bronchoalveolar leucocytes, to damage the connective tissue molecule fibronectin. Inflammatory bronchoalveolar leucocytes had greater ability to mediate connective tissue damage than had resident alveolar macrophages and the tissue proteolysis was mediated, in the main, by proteinases active at neutral rather than at acid pH. The increased secretion of proteinase by inflammatory leucocytes was dependent on in vivo stimulation: exposing resident or inflammatory bronchoalveolar leucocytes in vitro to particulate or soluble stimuli had no effect in increasing their ability to degrade fibronectin or secrete the inflammogenic proteinase, plasminogen activator. Thus, neutrophils in the bronchoalveolar region of the rat lung have proteolytic activity which is mediated largely by neutral proteinases.

BACKGROUND--The transit of neutrophils through the pulmonary microvasculature is prolonged compared with red blood cells and is increased further during cigarette smoking and in exacerbations of chronic obstructive pulmonary disease. The increased residence time (sequestration) of neutrophils in the pulmonary capillaries in these conditions may be the first step leading to the accumulation of cells within the lung interstitium and in the bronchoalveolar space, so potentiating lung damage. A rat model has been developed to investigate the factors which may influence neutrophil transit through the lung microvasculature. METHODS--Intratracheal instillation of the heat killed organism Corynebacterium parvum was used to induce an acute neutrophil alveolitis. Neutrophils and red blood cells were isolated from donor rats, labelled with two distinct radioisotopes, and then reinjected into recipient rats to assess their transit through the pulmonary circulation. To ascertain whether peripheral blood neutrophils were minimally altered by the isolation procedure their functional status in vitro was compared with that of inflammatory neutrophils in a number of assays commonly used as descriptors of neutrophil activation. The influence of neutrophil activation on the accumulation of cells in the lungs was assessed by comparing the lung sequestration of control neutrophils, isolated from peripheral blood, with that of inflammatory neutrophils obtained from bronchoalveolar lavage of inflamed rat lungs. Lung sequestration of neutrophils was defined as the fold increase in the ratio of neutrophils labelled with chromium-51 to red blood cells labelled with technetium-99m in lung tissue compared with the same ratio in peripheral blood. RESULTS--Sequestration of peripheral blood neutrophils occurred in control rat lungs as shown by a 17.5 (2.1) fold increase in the ratio of neutrophils to red blood cells in the pulmonary circulation compared with the ratio of these cells in the peripheral circulation. When inflammatory neutrophils, obtained by bronchoalveolar lavage from C parvum-treated animals, were injected into control rats, the increase was 90.6 (11.0) fold. Induction of an inflammatory response in the lung tissue of the recipient rat also caused an increase in the sequestration of control neutrophils compared with the same cells in control rat lungs which was, however, less marked than when inflammatory neutrophils were used (34.7 (4.7) fold). The mean (SE) pressure developed on filtration of inflammatory neutrophils in vitro through a millipore filter (7.53 (0.2) cm H2O) was greater than that of peripheral blood neutrophils (1.18 (0.2) cm H2O). Increased filtration pressure indicates a decrease in cell deformability and suggests that this may be a contributory factor to the increased sequestration of inflammatory neutrophils in the pulmonary vasculature. CONCLUSIONS--This study shows that there is sequestration of neutrophils in the pulmonary vasculature in normal rat lungs which increases in acute lung inflammation and when inflammatory neutrophils are injected into control animals. In this model changes in the neutrophil, such as cell deformability, may have a more important role in inducing increased neutrophil sequestration than the inflammatory response in the lungs.

Autologous implants of genetically modified fibroblasts may be an ideal approach to gene replacement therapy. However, primary fibroblasts have limited life span and their use for gene therapy is questionable. We have developed a rat model to evaluate the feasibility of this approach. Primary fibroblasts initiated from rat skin biopsies were transfected with plasmid DNA. The transkaryotic fibroblasts were implanted into the original rat donors. A plasmid-encoded gene product, human growth hormone, was detected in the donor rats' circulation but less than 1% of the expected amount was recovered. Implantation at intraperitoneal, intramuscular or subcutaneous sites were effective in delivering the novel gene product. Fluctuating levels of human growth hormone were detected for over 6 months but their determination was rendered unreliable due to interference by extremely high titers of antibodies developed against the human growth hormone. In some cases, the antibody titer continued rising for more than 6 months, indicative of the continued presence of the antigen. One of the recipients developed two intra-abdominal fibrosarcomas that were shown to be derived from the implanted cells. In conclusion, this model demonstrates that autologous fibroblast implantation is a feasible approach to delivering novel gene products lasting for several months. Strong and prolonged immuno-reaction against the gene product will occur if the recipient's immune system is naive to the replacement product, as would occur in patients with CRM- mutations. The potential for neoplastic development from the implanted fibroblasts should prompt further evaluation of the long-term safety in gene replacement therapy.

The aim of this study was to determine the bronchoalveolar leukocyte response to airborne coal mine dust; quartz and titanium dioxide were used as positive and negative controls, respectively. Groups of rats were exposed to airborne mass concentrations of 10 and 50 mg/m3 of the dusts for 7 hr/day, 5 days/week and their bronchoalveolar space was lavaged at time points between 2 and 75 days of exposure, to assess the leukocyte response. This study revealed time-dependent and airborne mass concentration-dependent recruitment of neutrophils and macrophages into the bronchoalveolar region with coal mine dust inhalation but no real difference in the magnitude of the response between coal mine dusts from collieries mining coal of different rank and quartz content although the maximum quartz content in the dusts used was 6%. The inflammatory response was much less than that produced by quartz, at similar airborne mass concentrations, and more than that produced by titanium dioxide which was, in general, a poor inflammogen in the rat lung. Groups of rats were exposed to the airborne dusts for 32 or 75 days, then removed from the exposure chambers, and allowed to recover by breathing room air for a further 64 days. During this recovery period there was marked progression of the leukocyte response with quartz and persistence of the response with coal mine dust. Chronic recruitment of leukocytes to the lungs of individuals inhaling coal mine dust is likely to be an important factor in the development of coal workers' pneumoconiosis.

In a previous study assessing respiratory symptoms in individuals employed in wool textile mills in the north of England relations between symptoms of chronic bronchitis, breathlessness and wheeze, and rhinitis and current exposure to airborne mass concentration of dust were shown. As preliminary steps in defining the potential hazard associated with dust from the air of wool mills the ability of inspirable dust, collected from the air of wool textile mills, to cause inflammation when injected into the lungs of rats was determined. Dusts were collected from the beginning of wool processing (opening) in one factory and from the middle (combing) and late (backwinding) stages of the process in two other factories. Ability of the dusts to cause inflammation was assessed by instillation into the lungs of rats followed by bronchoalveolar lavage. All the dusts caused some inflammation which peaked on day 1 and did not persist beyond one week. A distinctive aggregation response of mononuclear cells in the lavage, however, had a different time course, peaking at day 7. An attempt was made to determine how the wool mill dusts caused inflammation and experiments showed that the dusts themselves had no inherent chemotactic activity but that they did have a pronounced ability to generate chemotaxins in serum and so could activate complement in lung fluid. In addition, dust collected from ledges in the mills had the ability to injure epithelial cells in vitro which could also contribute to inflammation. A role for endotoxin in the inflammatory activity of the dusts was not discounted and a leachate of the dust had the ability to cause inflammation when injected into the lungs of rats. Wool mill dust is likely to be a complex mixture of materials and these experiments represent a preliminary approach to understanding the biological activity of the whole unfractionated dust and further studies are in progress to define more accurately the toxic material(s) in the dust.

In all mammalian species studied to date, the pineal gland shows a pronounced circadian rhythm with high activity at night and very low activity in daytime, as reflected in the output of its hormone, melatonin. The pineal is one of the few organs which can synthesize melatonin and, under normal circumstances, is virtually the only source of circulating melatonin. Pineal activity is tightly controlled by the light/dark cycle, in such a manner that melatonin can convey information to the organism on the length of the dark phase of the photoperiod. In seasonal breeding species, the 24 hour pattern of secretion of melatonin shows seasonal changes which are crucial for determining the timing of seasonal changes in bodily function. In man, alterations in pineal function are of significance in jet-lag, shift work and in affective disorder.

Samples of the chrysotile taken during and after treatment by the wet dispersion process have been tested for their cytotoxic effect in vitro and the results compared with both a UICC chrysotile A sample and a dust prepared from a standard chrysotile textile yarn. Results were obtained from three different in vitro assay systems utilizing P388D1, V79-4 and A549 cells. A sample which still contained the wetting agent used in the wet dispersion process failed to show activity in any of these assays. The other samples, however, were all active with those dusts obtained by milling the final product and by sampling the air of the factory consistently proving significantly more cytotoxic than the standard chrysotile controls. Preliminary results from a parallel in vivo study suggest that these samples are also more active in producing mesotheliomas in rats.

Chronic exposure to coalmine dust is associated with the accumulation of inflammatory leukocytes in the bronchoalveolar region of the lung and, in the long term, with fibrosis and emphysema of the lung parenchyma. Degradation of connective tissue by inflammatory leukocytes has been implicated in the parenchymal damage that precedes the development of fibrotic or emphysematous lesions in the lung. The ability of inflammatory leukocytes obtained by bronchoalveolar lavage from rats inhaling coalmine dust to degrade fibronectin in vitro was assessed. The animals were exposed to an airborne mass concentration of dust similar to the maximum permissible level in United Kingdom collieries. The bronchoalveolar lavage cell population showed changes with duration of dust exposure; there were increases in the total number of leukocytes and in the percentage of polymorphonuclear leukocytes, and the macrophage component of the lavage became increasingly activated, as assessed by the ability of these cells to spread on glass. In addition, degradation of a radiolabelled fibronectin matrix by the coalmine dust exposed bronchoalveolar leukocytes increased with duration of dust exposure. Thus exposure to airborne coalmine dust causes an influx of inflammatory leukocytes to the alveolar region. These cells have enhanced ability to degrade fibronectin and this may be important in subsequent disease development.

Previous studies have shown that long thin asbestos fibres are more pathogenic in in vivo and more active in in vitro assays than short fibre samples. In the present study a long fibre amosite asbestos sample and a short fibre sample prepared from it were tested for ability to cause inflammation in the peritoneal cavity of the mouse; a UICC sample intermediate in fibre size and an inert compact dust, TiO2, were also tested. The ability of the dust samples to cause inflammation, as judged by macrophage and neutrophil recruitment, was ranked in the order long fibre greater than UICC greater than short fibre greater than TiO2. Ability of amosite samples to cause inflammation was therefore related to the proportion of long fibres. The enhanced ability of long fibres to cause inflammation and cause macrophage activation is probably a key factor in the ability of long fibres to cause pulmonary fibrosis and may also be important in fibre carcinogenesis.

Cardiovascular status and reactivity have been investigated in spontaneously hypertensive rats (SHR) with glycerol-induced acute renal failure. SHR with acute renal failure had significantly lower mean arterial blood pressures and heart rates. The pressor responses to noradrenaline and the chronotropic responses to right cervical sympathetic and vagal nerve stimulation were diminished in uraemic SHR compared to control SHR. The cardiovascular depression observed in SHR with acute renal failure was similar to that previously noted in normotensive rats with acute renal impairment.

An enzyme immunoassay test was developed for detecting the A and M antigens of brucellae. One hundred fifteen isolates, including 96 strains of Brucella abortus, 5 strains of B. suis, 1 strain of B. melitensis and 1 strain of B. neotomae, were accurately serotyped with the enzyme immunoassay test. No reactions were observed with 11 isolates of B. canis and 1 isolate of B. ovis. This rapid serological test provides for considerable savings in time and materials as compared with the standard tube agglutination test.

Rat mesothelial cell cultures were shown to have considerable plasminogen dependent and independent fibrinolytic activity in vitro using an 125I fibrin degradation assay. At non-toxic doses of the mineral dusts titanium dioxide, quartz and crocidolite asbestos, as assessed by 51Cr release, the fibrinolytic activity of mesothelial cells was inhibited. Quartz had the greatest inhibitory effect and crocidolite asbestos had the least. These results suggests that inhibition of mesothelial cell fibrinolysis does not, on its own, explain pleural fibrosis due to toxic mineral dusts.

Inflammatory leucocytes are implicated in connective tissue damage during chronic inflammatory lung disease. In an investigation of the role of leucocytes in connective tissue derangements in the lung, inflammatory leucocytes were generated in rat lungs by intratracheal instillation of inflammatory agents and retrieved by bronchoalveolar lavage. The proteolytic activities of control macrophages and of two inflammatory cell populations were compared; iodinated collagen, laminin, and fibronectin matrices were used. The inflammatory cells caused consistently and substantially more degradation of the matrices than the controls on a per cell basis. The oxidant scavengers superoxide dismutase and catalase did not inhibit matrix degradation, but alpha 1 protease inhibitor and alpha 2 macroglobulin were inhibitory. It is concluded that matrix damage in this assay is enhanced by inflammatory cells and is mediated principally by serine protease activity.

The enzyme system responsible for the conversion of 2-amino-4-oxo-6-(D-erythro-1',2',3'-trihydroxypropyl)-7,8-dihyd roptridine triphosphate (dihydroneopterin triphosphate or H2-NTP) to 2-amino-4-oxo-6-acetyl-7,8-dihydro-3H,9H-pyrimido[4,5-b]-[1,4]diazepine (pyrimidodiazepine or PDA), a precursor to the red eye pigments, he drosopterins, has been purified from the heads of Drosophila melanogaster. The PDA-synthesizing system consists of two components, a heat-stable enzyme and a heat-labile enzyme. The heat-stable enzyme can be replaced by sepiapterin synthase A, a previously purified enzyme required for the Mg2+-dependent conversion of H2-NTP to an unstable compound that appears to be 6-pyruvoyltetrahydropterin (pyruvoyl-H4-pterin). The heat-labile enzyme, purified to near-homogeneity and termed PDA synthase (Mr = 48,000), catalyzes the conversion of pyruvoyl-H4-pterin to PDA in a reaction requiring the presence of reduced glutathione. Because PDA is two electrons more reduced than pyruvoyl-H4-pterin, the reducing power required for this transformation is probably supplied by glutathione. The PDA-synthesizing system requires the presence of another thiol-containing compound such as 2-mercaptoethanol when incubation conditions 2-mercaptoethanol is no longer required. Evidence is presented to indicate that the Drosophila eye color mutant, sepia, is missing PDA synthase.

La presence de poussiere minerale dans le poumon de rats augmente le nombre de macrophages et de neutrophiles dans la region bronchoalveolaire, durant l'exposition. Ces cellules produisent, en grandes quantites, une protease capable de degrader la fibronectine du tissu conjonctif. Elle jouerait un role important dans le developpement d'une pathologie pulmonaire

In order to characterize the effects of a septal lesion on plasma growth hormone levels, blood samples were taken from normal and sham-operated rats and rats with a bilateral septal lesion under conditions of rest and following stressful stimulation. Nonlesioned control rats evidenced a significant base line diurnal rhythm in plasma growth hormone levels which was unaffected by a septal lesion. In response to stress, plasma growth hormone levels evidenced a significant drop. Minimum levels were reached 15 min after stimulation and remained depressed during 1 hr of observation after stimulation. Rats with a septal lesion evidenced the same pattern of growth hormone response to stressful stimulation as nonlesioned rats, however the magnitude of response was potentiated in septal rats. The present data were compared to the previously published corticosterone data from the same animals. A septal lesion has similar effects on boting 24-hour rhythm of either of these hormones but potentiated the response of both corticosterone and growth hormone to stress even though the direction of response is opposite. The results are interpreted as suggesting the septum is an element in some central coping mechanism which is involved when an organism reacts to environmental demands. Preliminary data further suggest that the same central coping mechanism is involved in both the behavioral and hormonal responses to stress.

The kinetics of the bronchoalveolar response was assessed in rats exposed, at equal airborne mass concentration (10 mg/m3), to titanium dioxide--a non-pathogenic dust--and the two pathogenic mineral dusts quartz and chrysotile asbestos. Rats were killed at intervals over a 75 day exposure period and groups of rats exposed for 32 and 75 days after recovery for two months. Bronchoalveolar lavage was carried out and the lavage fluid characterised for cellular content, macrophage activation, and concentrations of free total protein, lactate dehydrogenase, and N-acetyl-beta-D-glucosaminidase. Inhalation exposure to the two pathogenic dusts resulted in an increased number of leucocytes, macrophage activation, and increased levels of free enzymes and total protein. The pattern and magnitude of the responses to quartz and chrysotile differed. Chrysotile caused less inflammation than quartz, and the main cellular response peaked around the middle of the period of dust exposure whereas the highest levels of enzymes occurred towards the end. The difference in timing suggests that macrophages were not available for lavage towards the end of the exposure, owing to their playing a part possibly in deposition of granulation tissue. Quartz caused a greater cellular and enzyme response than chrysotile, particularly towards the end of the dust exposure phase. There was a noticeable progression of inflammation in the quartz exposed groups left to recover for two months, but not in the chrysotile recovery groups.

The compound 2-amino-4-oxo-6-acetyl-7,8-dihydro-3H,9H-pyrimido[4,5-b]-[1,4]diazepine (pyrimidodiazepine or PDA, for short) is a precursor of the red eye pigments called the drosopterins in Drosophila melanogaster. The precursor of PDA is 2-amino-4-oxo-6-(D-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydrop teridine triphosphate (dihydroneopterin triphosphate or H2-NTP). The synthesis of of PDA from H2-NTP requires reduced glutathione, another thiol such as 2-mercaptoethanol, Mg2+, and at least three enzymes: one that is missing in the eye color mutant, sepia; one that is present only in limited quantities in the mutant, clot; and a third one that has been described as sepiapterin synthase A. The last enzyme is present only in relatively small quantities in the mutant, purple. Because PDA is two electrons more reduced than H2-NTP, it would appear that the reducing power needed for this transformation is probably supplied by glutathione. Oxidized glutathione cannot replace reduced glutathione in the system. The yield of PDA produced enzymatically from H2-NTP can be as high as 40% under optimal conditions.

Sensitivities of two enzyme-linked immunosorbent assays (ELISAs) with particulate and sodium dodecyl sulfate (SDS)-disrupted Anaplasma marginale antigen were compared. The quotient of positive reference sera divided by the absorbance quotient of a negative reference serum at identical dilution was termed the signal-to-noise ratio. Optimal signal-to-noise ratios were dependent on both pretreatment of antigen and antigen concentration. SDS disruption of anaplasmal antigen resulted in a markedly improved signal-to-noise ratio of ELISA compared with ELISA with untreated antigen at identical antigen and serum dilutions. This represented higher sensitivity and lower background absorbance of the ELISA with disrupted antigen. SDS-disrupted A. marginale antigen was standardized by protein determination, and antigen, as well as precoated microtiter wells, was stored frozen without apparent loss of antigenic properties. ELISA results were in agreement with results of positive and negative control sera tested by the complement fixation test or by light microscopy Anaplasma diagnosis in Giemsa-stained blood films.

In a serologic and blood culture survey for Brucella canis in 2,572 pound dogs from eight Illinois and Wisconsin counties, 173 (6.7%) were reactive in a presumptive slide test, 41 (1.5%) were reactive in a tube agglutination test, and 6 (0.2%) were positive in blood culture.

The biological properties of quartz have been related to its surface reactivity. We have addressed the role of particle surface reactivity in mediating the biological activity of quartz in mixed dusts, by treating the quartz with aluminum lactate. Intratracheal instillation of untreated quartz in rats caused a rapid, sustained alveolitis and bronchoalveolar leukocytes obtained from these animals had enhanced activity in degrading fibronectin, but reduced ability to mount a respiratory burst. Quartz pretreated with aluminum elicited a markedly reduced inflammatory response; the reduced activity of the treated quartz was also reflected in the attenuated change in the key functional parameters, oxidant production and proteolysis of fibronectin. Late intratracheal dosing with aluminum after the quartz-induced alveolitis was well established reduced the inflammatory response and abrogated the effect of quartz on the respiratory burst, but did not alter fibronectin degradation by the leukocytes. Aluminum did not affect the inflammatory response to Corynebacterium parvum and thus the effect was on the quartz particles and not on the inflammatory leukocytes. These findings have implications for the likely pulmonary responses to mixed dusts containing quartz and aluminum silicate clays.

The investment into the design of a study is usually and unfortunately proportional to the available information, i.e. the less one knows the more one is tempted to skimp and perform a minimal 'pilot' study. This is particularly true with respect to chronobiology. On the contrary, at the outset of a study, when the information available regarding a given problem is minimal or zero, the investment into a first study should be near-maximal. Accordingly, the often wasted 'pilot study' should be replaced by a rigorous chronobiologic lead study. The promise of such a chronobiologic 'guide, leading along a difficult or unknown course' is illustrated by the validation with statistical significance of an about-weekly (circaseptan) and an about 24-h (circadian) rhythm in the melatonin content of the murine pineal. Work around the clock on 48 female Lewis/S rats was avoided. Replication of 6 different circadian times on different comparable animals on consecutive days assessed a circaseptan rhythm more prominent than the concomitantly demonstrated circadian, at no added cost for experimental animals beyond those often used for circadian study and with no work around the clock.

For melatonin (a chronomodulator of adrenal cortical function, immune phenomena and carcinogenesis), a circadian rhythm is demonstrated in aqueous pineal homogenate of domesticated B6D2F1 mice. Domestication as such does not eliminate a mechanism of cephalo-adrenal coordination.

A compound that is involved in the biosynthesis of the drosopterin eye pigments has been isolated from the heads of Drosophila melanogaster. Analyses of this compound by chemical, mass spectral, and proton nuclear magnetic resonance techniques in conjunction with biochemical considerations provide evidence for the structure 2-amino-4-oxo-6-acetyl-7,8-dihydro-3H,9H-pyrimido[4,5-b][1,4]diazepine (PDA). At least three eye pigments (drosopterin, isodrosopterin, and aurodrosopterin) are synthesized when PDA and 2-amino-4-oxo-(D-erythro-1',2',3'-trihydroxypropyl)-7.8-dihydropteridine triphosphate (dihydroneopterin triphosphate) are incubated with Mg2+ and protein fractions prepared from Drosophila heads. The synthesis of aurodrosopterin, in addition, requires reduced pyridine nucleotide. Other evidence suggests that dihydroneopterin triphosphate is a biosynthetic precursor of PDA.

Dopamine receptors in the central nervous system can be studied by measuring the specific binding of [3H]dopamine, [3H]haloperidol, d-[3H]LSD, [3H]dihydroergocryptine or [3H]apomorphine. The receptors are stereoselectively blocked by +)-butaclamol, a neuroleptic. All neuroleptics inhibit the specific binding of [3H]haloperidol in relation to their clinical potencies. The radioligand that desorbs most slowly from the receptor is [3H]apomorphine, thus making it a reliable ligand for dopamine receptors. Dopamine agonists that compete for [3H]apomorphine binding do so at concentrations that correlate with their potency in stimulating striatal adenylate cyclase. Structure-activity analysis, using [3H]apomorphine, confirms that the active dopamine-mimetic conformation is the beta rotamer of dopamine. Prolonged exposure in vitro of caudate homogenate to high concentrations of dopamine leads to increased binding of [3H]apomorphine or [3H]haloperidol, suggesting receptor "sensitization." Chronic haloperidol treatment of rats leads to an increased number of dopamine/neuroleptic receptors in the striatum, but a decrease in the pituitary.

The enzyme, previously called "sepiapterin synthase A," has been purified by approximately 700-fold from the heads of Drosophila melanogaster. This enzyme catalyzes the Mg2+-dependent conversion of 2-amino-4-oxo-6-(D-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydrop teridine triphosphate (dihydroneopterin triphosphate or H2-NTP) to two products, one of which we have identified as tripolyphosphate. The other product is a phosphate-free, unstable compound which is an intermediate in the biosynthesis of several other naturally occurring pterins in Drosophila. This product is stable enough under anaerobic conditions to allow it to be characterized as 6-pyruvoyl-5,6,7,8-tetrahydropterin (6-pyruvoyl-H4-pterin). The 3-carbon side chain was identified as a pyruvoyl group on the basis of the susceptibility of the enzymatic product to reduction with tritiated sodium borohydride and the determination of the amounts and the sites of incorporation of tritium resulting from this reduction. From these observations, we suggest that this enzyme be renamed "6-pyruvoyl-H4-pterin synthase."

Nachweis, dass bei ausgewachsenen Totenkopfaffen (Saimiri sciureus) die Zellkerndurchmesser im Nucleus ventromedialis hypothalami in der Periode der hochaktiven Spermiogenese kleiner sind als zu Beginn der Brunstperiode. Da das limbische System mit diesem Kern zusammenhangt, sind direkte Einflusse nicht auszuschliessen.