Cohort study among workers exposed to benzene in China: I. General methods and resources

Benzene is recognized internationally as a leukemogen, but the available data to clarify dose-response relationships and examine risks of malignancies other than leukemia are sparse. A collaborative study was therefore carried out to expand on a previous retrospective cohort mortality study of Chinese benzene-exposed workers. Methods and resources used in the 16-year follow-up of 74,828 benzene-exposed and 35,805 unexposed workers employed for any length of time during 1972-1987 in 712 factories in 12 cities in China are described. Details are provided of the study organization, assessment of benzene exposures since 1949, characterization of factories and workers by exposure status, city, and sex, identification and confirmation of cancers and other deaths, and quality control procedures. The distinguishing features of the study are discussed in relation to earlier cohort studies, and study limitations as well as strengths are presented.

Cohort study among workers exposed to benzene in China: II. Exposure assessment

This report describes a retrospective exposure assessment method used in a follow-up mortality study of workers exposed to benzene. The approach quantified historical exposure to benzene in a multi-industry, multicenter cohort, involving 672 factories in 12 cities in China. Historical exposure data were collected to obtain exposure information related to 1,427 work units (departments) and 3,179 unique job titles from benzene-producing or -using factories in which written records and other data sources were evaluated. The basic unit for exposure assessment was a factory/work unit/job title combination which was considered separately during each of seven calendar-year time periods between 1949 and 1987 for a total of 18,435 exposure assignments. Historical information collected to estimate exposure included benzene monitoring data; lists of raw materials and factory products, and the percentage of benzene in each; the total amount and dates of use of benzene or benzene-containing materials; use of engineering controls and personal protective equipment; and other available exposure information. Overall, 38% (ranging from 3% for the earliest periods to 67% for the last period) of the estimates were based primarily on benzene monitoring data. In the absence of job-specific benzene monitoring data for a given calendar period, measurement results or exposure estimates for similar jobs and/or other calendar periods were used in conjunction with other exposure information to derive estimates. Estimated exposure levels are presented by industries and occupations. The highest average exposures during 1949-1987 were observed for the rubber and plastic industry (30.7 ppm), and for rubber glue applicators (52.6 ppm).

Gender differences in hematopoietic and lymphoproliferative disorders and other cancer risks by major occupational group among workers exposed to benzene in China

Gender differences in risk for leukemia and other selected and combined disease categories were examined by major occupational category for 74,828 benzene-exposed workers compared to 35,805 unexposed workers from 12 cities in China. No significant differences in the relative risks for total mortality and cancer mortality were found between female and male benzene-exposed workers, although risks tended to be somewhat higher among male than among female employees. Both female and male workers in several occupational categories had notably increased risks for all hematopoietic and lymphoproliferative (HLP) malignant and nonmalignant disorders combined and for total leukemia. Variation in risk for HLP disorders by occupational category was observed in both genders, with highest risks for male and female chemical manufacturing workers, female nonproduction employees, and male printers. However, the numbers of leukemia and other HLP malignancies in each category were small. The findings suggest that both female and male benzene-exposed workers in several occupational categories experience excess leukemia and other HLP disorders with relatively minor gender differences. Although this population is one of the largest cohorts of benzene-exposed workers studied to date, evaluation of the observed variation in risk for HLP neoplasms among the occupational groups for workers of each gender is limited by the small numbers of these relatively rare malignancies.

Enhanced tissue responsiveness in colonic ion transport of cow's milk-sensitized guinea pigs

The effects of leukotriene D4 (LTD4) on ion transport were investigated in submucosa/mucosa colonic segments from guinea pigs sensitized to cow's milk and in age-matched, non-immune animals. Mediators released from mast cells in immune animals challenged with beta-lactoglobulin evoked an increase in short-circuit current that was reduced by SK&F 102922, a peptidoleukotriene antagonist. Serosal addition of LTD4 (0.15-1 microM) evoked a concentration-dependent, bumetanide-sensitive increase in short-circuit current which was greater in immune than non-immune controls. In the absence of ongoing neural activity, 1 microM LTD4 evoked an 8-20 microA/cm2 increase in short-circuit current which was increased 8-13-fold when ongoing neural activity was present. In tissues with ongoing activity, the response to 0.15 microM LTD4 was reduced by SK&F 102922, tetrodotoxin and atropine. LTD4 enhanced the responsiveness of the tissue to carbachol by a factor of two, but did not affect responses of T84 colonic epithelial cell monolayers to this agent. These results show enhanced secretory function for LTD4 in animals with allergy to cow's milk. They suggest that the level of ongoing neural activity in the enteric neural microcircuits is one of the major determinants of colonic secretory capacity.

Immunohistopathological study of autoimmune pemphigus. Lack of strictly specific histological and indirect immunofluorescence criteria for paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) is a form of pemphigus considered to bear characteristic immunohistopathological features (vacuolar-interface dermatitis, keratinocyte dyskeratosis and reactivity of patients' sera with transitional epithelia). The present study was undertaken in order to investigate whether these criteria are specific enough so as to allow the diagnosis of PNP in the absence of clinical data. A retrospective study of 66 biopsies of pemphigus revealed that one third of them comprised histological signs of PNP; one of the corresponding sera reacted with mouse bladder epithelium. However, no evidence of a neoplastic disease was present in any of the patients, and Western blotting further excluded the diagnosis of PNP. These results suggest that some of the features considered characteristic of PNP are not strictly specific for this variety of pemphigus; hence this diagnosis cannot be reliably established by histology or immunofluorescence but requires biochemical studies.

Effect of 1,25,28-trihydroxyvitamin D2 and 1,24,25-trihydroxyvitamin D3 on intestinal calbindin-D9K mRNA and protein: is there a correlation with intestinal calcium transport?

Although analogs and metabolites of vitamin D have been tested for their calciotropic activity, very little information has been available concerning the effects of these compounds on gene expression. In this study one analog of vitamin D, 1,25,28-trihydroxyvitamin D2 [1,25,28-(OH)3D2], and one metabolite, 1,24,25-trihydroxyvitamin D3 [1,24,25-(OH)3D3], were tested for their effect on intestinal calbindin-D9K mRNA and protein as well as for their effect on intestinal calcium absorption and bone calcium mobilization. These compounds were also evaluated for their ability to compete for rat intestinal 1,25-(OH)2D3 receptor sites and to induce differentiation of human leukemia (HL-60) cells as indicated by reduction of nitro blue tetrazolium. In vivo studies involved intrajugular injection of 12.5 ng 1,25-(OH)2D3 or test compound to vitamin D-deficient rats and sacrifice after 18 h. 1,25,28-Trihydroxyvitamin D2 had no effect on intestinal calcium absorption, bone calcium mobilization, or intestinal calbindin-D9K protein and mRNA. Competitive binding to 1,25-(OH)2D3 receptors was 0.8% of that observed using 1,25-(OH)2D3. However, 20- and 40-fold higher doses of 1,25,28-(OH)3D2 (250 and 500 ng) resulted in significant inductions in calbindin-D9K protein and mRNA (3.5 to 7.4-fold), although doses as high as 800 ng were found to have no effect on intestinal calcium absorption or bone calcium mobilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Coordination of Cl- secretion and contraction by a histamine H2-receptor agonist in guinea pig distal colon

Short-circuit current (Isc) was measured simultaneously with muscle tension recorded in the longitudinal or circumferential axis from strain-gauge transducers sutured to the serosal surface of whole thickness segments of distal colon from guinea pigs. Isc and the amplitude and frequency of small-amplitude phasic contractions were stable for several hours. The histamine H2-receptor agonist dimaprit (5-10 microM) evoked recurrent increases in Isc at a frequency of 0.32-0.37 cycles/min. Associated with each cyclical Isc response was an increase in muscle tension indicative of large-amplitude phasic contractions. Recurrent cycles of Isc and associated large-amplitude phasic contractions were abolished by 10 microM cimetidine. In the presence of dimaprit, severing the neural connections between the myenteric and submucosal plexuses abolished the large-amplitude phasic contractions but not cyclical Isc. The results suggest that coordination of cyclical secretion and large-amplitude contraction during chronic activation of histamine H2 receptors requires intact neural connections between the submucosal and myenteric plexuses. The findings provide potential mechanisms to explain altered motility and ion transport during inflammatory diseases or allergic responses to food antigens.

Responses of human fetal splenocytes and thymocytes to interleukin-2 and comparison with adult peripheral blood lymphocytes

By means of cytotoxicity and thymidine uptake assays, the effect of human recombinant interleukin-2 (rIL-2) on the induction of lymphokine-activated killer (LAK) cell activity and cellular proliferation in splenocytes and thymocytes from human fetuses (18-22 weeks) was studied and compared with that in mononuclear cells from adult peripheral blood. It was shown that the fetal splenocytes and thymocytes incubated with low doses of rIL-2 (10-100 U/ml) developed a broad spectrum of antitumor activity (LAK cytotoxicity), although the kinetics and magnitudes of the responses were different. It was also suggested that LAK precursors were present in fetal spleen and thymus. Furthermore, rIL-2 induced a stronger proliferative and cytotoxic response in splenocytes than in thymocytes. The human fetal LAK cells isolated from the spleen were found to be 10-20 times more potent than those from adult peripheral blood with regard to cell proliferation and cytotoxicity in vitro.

A novel antigen of the dermal-epidermal junction defined by an anti-CD1b monoclonal antibody (NU-T2)

NU-T2 is a mouse monoclonal IgG1 antibody to the CD1b molecule, (cross-)reacting with an antigen of the dermal-epidermal junction (NU-T2 DEJ AG). Further immunohistochemical characterization of the NU-T2 DEJ AG showed it to display unique properties that differentiate it from other known antigens of the dermal-epidermal junction. Indeed, the NU-T2 DEJ AG is primate-specific and present only in epithelial basement membranes. In normal human skin it is expressed within the lowermost lamina lucida of the dermal-epidermal junction but not in the deep part of epidermal appendages nor in the deep part of epidermal appendages nor in the basement membrane of dermal vessels, smooth muscles or nerves. In diseases with intraepidermal or intradermal cleavage, NU-T2 reactivity was observed at the floor of the blister. In various skin specimens with a cleavage through the lamina lucida (NaCl--or dispase-split skin, bullous pemphigoid, junctional epidermolysis bullosa), NU-T2 immunoreactivity seemed reduced, being localized at the dermal side of the cleavage. These results suggest that the antigen recognized by NU-T2 is a novel component of the lamina lucida of the dermal-epidermal junction, that seems to be important for dermal-epidermal adhesion.

CT detection of wrist bone erosion in rheumatoid arthritis

A correlative radiographic and CT study of the wrists of 30 patients with rheumatoid arthritis (RA) was reported. The results showed that sensitivity of CT in detecting wrist erosion is superior to that of conventional radiograph. Accordingly, wrist CT scanning is useful for early diagnosis of RA.

[Screening of anti-simian immunodeficiency virus (SIV) drugs from Chinese medicinal herbs]

The inhibitory activities of more than 40 species of Chinese medicinal herbs or their single chemical components against simian immunodeficiency virus (SIV) have been studied. The study revealed that four species of the medicinal herbs and a single chemical component had more than 50% inhibition of SIV antigen expression and five other herbs' inhibitory rate of SIV antigen expression was between 30-50%. The results showed that Chinese medicinal herbs could inhibit the SIV activity.

Effects of selenium deficiency on Ca transport function of sarcoplasmic reticulum and lipid peroxidation in rat myocardium

Two groups of weanling Sprague-Dawley rats were fed a low-selenium basal diet (Se 0.009 mg/kg) and the same diet supplemented with sodium selenite (Se 0.25 mg/kg), respectively, for 1, 2, and 3 months. At each feeding time, the Ca(2+)-ATPase activity, Ca2+ uptake rate and the capacity of Ca2+ uptake in isolated cardiac sacroplasmic reticulum from the Se-deficient rats were decreased significantly compared to those from the Se-supplemented rats, the contents of lipid peroxide in postmitochondrial supernatant and isolated sarcoplasmic reticulum from the Se-deficient rats were significantly higher than that from Se-supplemented rats. Compared to the Se-supplemented rats, the cytosolic glutathione peroxidase activity in Se-deficient rats decreased significantly. In addition, significant linear negative correlations of lipid peroxide in postmitochondrial supernatant to sarcoplasmic reticular Ca(2+)-ATPase activity, Ca2+ uptake rate and to whole blood selenium concentration were observed. The results suggest that the enhancement of lipid peroxidation via the depressed glutathione peroxidase activity might be responsible for the decrease of Ca(2+)-ATPase and Ca2+ uptake activities in sarcoplasmic reticulum in Se-deficient animals.

Neuroimmune interactions: role for cholinergic neurons in intestinal anaphylaxis

The role of cholinergic neurons in mediating chloride secretion in anaphylaxis was assessed in muscle-stripped segments of distal colon from guinea pigs immunized to bovine milk. beta-Lactoglobulin evoked a concentration-dependent increase in short-circuit current (Isc) in immune, but not nonimmune, tissues. The Isc response to beta-lactoglobulin was reduced by piroxicam, pyrilamine, and cimetidine. Tetrodotoxin and atropine reduced the Isc response to beta-lactoglobulin in immune animals, whereas mecamylamine and ICS 205-930 were ineffective. beta-Lactoglobulin evoked a concentration-dependent increase in acetylcholine (ACh) release in immune, but not nonimmune, animals. In immune tissues after challenge with beta-lactoglobulin, ACh release paralleled the change in Isc. Piroxicam, cimetidine plus pyrilamine, or a combination of piroxicam, cimetidine, and pyrilamine significantly reduced the release of ACh after beta-lactoglobulin challenge. Histamine, dimaprit, and prostaglandins E2 evoked an increase in ACh release. These results suggest that beta-lactoglobulin releases prostaglandins and histamine probably from mast cells. Secretory responses that occur when immune animals are challenged with beta-lactoglobulin result, in part, from activation of cholinergic neurons that utilize muscarinic synapses for transfer of signals to the epithelium.

Loss of absorptive capacity for sodium and chloride in the colon causes diarrhoea in Potomac horse fever

Ehrlichia risticii, an obligate intracellular bacterium in the family Rickettsiaceae, causes Potomac horse fever which is often associated with severe watery diarrhoea. The mechanism of the diarrhoea is unknown. The aim of this study was to determine whether sodium and chloride transport, morphology and cyclic adenosine 3', 5'-monophosphate (cyclic AMP) content of colonic mucosa was altered in E risticii-infected horses. Mucosa-submucosa sheets from the large and small colon of nine infected and seven to nine uninfected horses were set up in Ussing chambers for measurement of short-circuit current and transepithelial 22Na and 36Cl fluxes. Uninfected tissues absorbed both sodium and chloride whereas absorption of sodium and chloride was abolished in infected tissues. Bethanechol and histamine evoked a concentration-dependent increase in short-circuit current in both groups, but the responses were attenuated at all concentrations in infected horses. Slight focal degeneration of colonic epithelial cells and loss of microvilli from glandular epithelial cells occurred in infected horses. There was a significant increase in cyclic AMP content in colonic mucosa of infected animals. The results suggest that E risticii infection induces focal microscopic degeneration of epithelial cells and an increase in intracellular cyclic AMP in colonic mucosa. These alterations are associated with malabsorption of sodium and chloride and could cause diarrhoea.

Ph-negative and bcr-negative atypical chronic myelogenous leukemia: biological features and clinical outcome

We report the clinical, hematologic, cytogenetic, and molecular characteristics of 13 patients with Philadelphia-negative (Ph-), bcr-negative atypical chronic myelogenous leukemia (CML). In the majority of cases, the phenotypic features at presentation resembled those of typical CML. However, these patients presented with a higher median age, lower median hemoglobin levels, and lower leukocyte and platelet counts than patients with Ph-positive CML. Cytogenetic analysis showed an abnormal karyotype in only one case. Southern blot investigation, using probes exploring the entire M-bcr region, demonstrated the absence of genomic bcr-abl rearrangements. The assessment of clonality in five patients (study of X-methylation patterns in females heterozygous at the DXS255 locus) indicated the proliferation of a monoclonal cell population. Disease evolution was mostly characterized by bone marrow failure, extramedullary infiltrates, and poor response to chemotherapy, without evidence of overt acute transformation. Our observations suggest that some hematologic and clinical features and the modalities of disease progression are presently the most helpful factors in distinguishing these bcr/abl-negative patients from those with typical bcr+CML. The differences existing also with chronic myelomonocytic leukemia (CMMoL), allow the consideration of ph-/bcr- CML as a separate entity, the nature of which remains to be elucidated.

Restriction endonuclease from thermophilic bacterial species. IV. Isolation and characterization of BpuB5I

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Neural 5-hydroxytryptamine receptors regulate chloride secretion in guinea pig distal colon

The effects of 5-hydroxytryptamine (5-HT) on epithelial short-circuit current (Isc) were determined and related to the 5-HT effects on electrical and synaptic behavior of neurons in the submucosal plexus of the guinea pig colon. 5-HT evoked a biphasic increase in Isc that was reduced by bumetanide, Cl(-)-free solutions, atropine, and mecamylamine and abolished by tetrodotoxin. The 5-HT response was mimicked by 2-methyl-5-HT, but not by 5-hydroxyindalpine, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, and 5-methoxytryptamine (5-MeOT). ICS 205-930 suppressed the 5-HT response. Electrical field stimulation of submucosal neurons evoked an increase in Isc indicative of Cl- secretion that was reduced by 5-MeOT and enhanced by 2-methyl-5-HT. Application of 5-HT to submucosal neurons by micropressure ejection resulted in membrane depolarization, augmented excitability, and repetitive spike discharge. The depolarization was biphasic, consisting of rapidly and slowly activating components. The rapidly activating component was suppressed by ICS 205-930. Fast excitatory postsynaptic potentials evoked by electrical stimulation of interganglionic connectives were suppressed by 5-HT and 5-MeOT. These results suggest that 5-HT activates 5-HT3 receptors, which mediate fast excitatory responses in submucosal neurons, leading to release of acetylcholine at nicotinic and muscarinic synapses and stimulation of Cl- secretion. Presynaptic inhibition suppresses acetylcholine release and results in attenuation of neurally evoked Cl- secretion.

Multidrug resistance activity in human lymphocytes

The multidrug resistance gene (mdr1) is a member of the recently described ATP binding cassette (ABC) superfamily of transporters. Family members include: (1) the cystic fibrosis transmembrane conductance regulator gene; (2) the hlyB gene of bacteria, and (3) the histocompatibility antigen modifier (HAM) gene. The level of expression of mdr1 correlates with multidrug resistance (MDR), the ability of cells to efflux otherwise toxic doses of several chemotherapeutic agents. MDR activity is also associated with the efflux of cationic lipophilic compounds such as the fluorescent dye rhodamine 123. Recently it was reported that normal lymphocytes efflux rhodamine 123, suggesting that these cells possess MDR-like activity due to the expression of mdr1. In this study, using two-color flow cytometric analysis, we observed that the ability to efflux rhodamine 123 was heterogeneous among human lymphocyte subsets in the order of CD8 greater than CD4 greater than CD2O. Rhodamine 123 efflux and accumulation in lymphocytes was sensitive to the known MDR reversing agents, verapamil and Solutol HS 15. Collectively, these data suggest that an MDR-like transport system is present in normal lymphocytes and may be important for trafficking of molecules involved in lymphocyte function.

[A study of IL-2 activity on lung cancer]

By using thymocytes of mice as target cells in bioassay, IL-2 production activity was investigated in 24 lung cancer patients, 24 noncancerous pulmonary lesions as well as 20 normal individuals. Fourteen cancer patients were reexamined after the first course of chemotherapy. This research demonstrated that: 1. PBL capable of IL-2 production in lung cancer patients were rare in comparison with benign disease or normal control. 2. IL-2 activity was markedly enhanced by chemotherapy. It is suggested that IL-2 is a good indicator for estimating the efficacy of treatment of lung cancer.

Application of pyridostigmine in evaluation of growth hormone reserves in children and adolescents

There is evidence that the cholinergic system positively modulates growth hormone (GH) secretion. In the present study, we observed the effects of cholinergic enhancement by pyridostigmine (PD), a cholinesterases inhibitor, on GH release in both normal (n = 13) and GH deficient children and adolescents (n = 10). Responses of GH to insulin hypoglycemia (Ins) were also observed. In the normal subjects, PD-induced serum GH peak level was significantly higher than that induced by Ins (P less than 0.01), while the GH level in the patients with pituitary dwarfism showed no increase in both tests. This study indicates that PD test may be considered a sensitive dynamic test in evaluating pituitary function of GH secretion in children and adolescents.

Chronic myeloid leukaemia lymphoid blast crisis. Relevance of molecular analysis at the bcr and immunoglobulin heavy chain gene level in monitoring response to therapy and residual disease

Southern blot analyses were performed in sequential DNA samples from 4 patients with Ph' + chronic myeloid leukaemia (CML) who underwent lymphoid or mixed blast crisis (BC). Genomic rearrangements at the breakpoint cluster region (bcr) and immunoglobulin heavy chain (IgH) gene level provided, in these cases, a sensitive and specific evaluation of response to therapy both in terms of blasts and Ph' + cell suppression. Recurrent BC was molecularly characterized in the 4 patients, showing each time identical individual specific DNA rearrangement patterns. Residual blasts were detected in 2 cases during intervening chronic phases by IgH rearrangements. Such findings highlight the specificity of these molecular markers, clearly indicating the failure of ablative therapy in eradicating the neoplastic clone. Finally, molecular and phenotypic identity in individual recurrent BC also suggested, in our cases, a lack of clonal evolution during disease progression.

Bone remodeling in hypervitaminosis D3. Radiologic-microangiographic-pathologic correlations

To investigate the mechanism of bone changes in hypervitaminosis D3, we compared contact radiographs, microangiograms by injection of Chinese ink, and corresponding histopathologic macrosections of 66 rabbits that received different doses of vitamin D3. In early stages, radiographs showed subperiosteal bone resorption and porotic cortical bone. The corresponding microangiograms showed proliferating vessels in the periosteum and cortical bone with associated dilatation of the Haversian and Volkmann's canals. When metastatic calcification fills these intracortical caverns or the intertrabecular spaces in the metaphysis and physis, the bone shows a diffuse increased density on radiographs. A dense band in the metaphysis reflects a thickening of calcified chondromatrix due to a hypotrophy of the distal metaphyseal capillaries. Six to 12 weeks after vitamin D3 withdrawal, radiographs showed further increased density of the cortical bone, due to newly formed bone and metastatic calcification. Alternating bands of increased and decreased density in the metaphysis and physis reflect the reinvasion of normal vasculature between growth cartilage and calcified chondromatrix, with normalization of endochondral ossification.

Neuroimmune regulation of colonic secretion in guinea pigs

The role of submucosal neurons in anaphylactic-like responses in colonic epithelium from immunized guinea pigs was examined 6-8 wk after inoculation with 2 x 10(3) infective Trichinella spiralis larvae. Serosal addition of T. spiralis antigen (20 micrograms/ml) to muscle-stripped segments of colon set up in flux chambers evoked a maximum increase in short-circuit current within 5 min in immune, but not nonimmune, guinea pigs. Quercetin, a membrane-stabilizing drug, and pyrilamine, a histamine H1 receptor antagonist, attenuated epithelial responses evoked by T. spiralis antigen. Antigen-induced epithelial responses were reduced by neural blockade with tetrodotoxin and by the muscarinic receptor antagonist atropine but not by blockade of nicotinic receptors with mecamylamine. Antigenic challenge of colonic mucosa from immune guinea pigs enhanced the secretory responses to endogenously released neurotransmitters evoked by electrical field stimulation and substance P. In the presence of antigen, the tetrodotoxin-insensitive component of the carbachol response was enhanced and was reversed by quercetin but not pyrilamine. The results suggest that submucosal cholinergic nerves play a role in mediating the rapid epithelial responses evoked by worm antigen in the colonic mucosa of T. spiralis-immune guinea pigs. Interaction of immunological mediators with neurotransmitters in the submucosal plexus augments the secretory mucosal response triggered by T. spiralis in immunized hosts.

Reassessment on roentgenologic signs of early rickets. Roentgenopathologic correlations of 52 en block specimens

Correlation of the X-ray manifestation and the en bloc sections of 52 wrists of infants and children aged from 0-4 years from autopsy was carried out to identify the real X-ray signs of rickets. Simple ill-defined provisional calcified zone (PCZ), enlargement of head of ulna, shallow saucer-shaped and undulant or multilaminar PCZ are normal in variation. The signs of early rickets included marginal spur, saucer-shaped deformity, ill-defined and disordered trabeculae under PCZ, mild brush appearance and osteoporosis. However, only when five of the above mentioned criteria were met at the same time, can early rickets be diagnosed.

Metastatic calcification within bone. The main cause of osteosclerosis in hypervitaminosis D3. Radiologic-pathologic correlation

Because the pathogenesis of osteosclerosis in hypervitaminosis D is still not well elucidated, the authors experimentally studied hypervitaminosis D3 in 66 rabbits by injecting different doses of vitamin D3. Contact radiographs of bone specimens showed various signs of osteosclerosis, including dense epiphyses and metaphyses, thickened bony articular surfaces, dense metaphyseal bands, modeling defects at the metaphysis, and dense and thickened cortical bone. The corresponding pathologic sections showed that conspicuous metastatic calcification coated the trabeculae and filled bone marrow cavity and caverns in the original but porotic cortical and periosteal new bone. Rather than being resorbed, the metastatic calcifications were embedded in a thick layer of newly formed bone 6 to 14 weeks after vitamin D3 withdrawal. This study suggests that in hypervitaminosis D3, the osteoblasts and bone marrow undergo degeneration, leading to necrosis and calcification. After vitamin D3 withdrawal, osteoblasts reappear and become overactive, leading to overossification.

H2 receptors mediate cyclical chloride secretion in guinea pig distal colon

We tested the hypothesis that histamine mediates ion secretion in the guinea pig distal colon by stimulating H2 receptors on submucosal neurons. Serosal addition of histamine evoked a transient increase in short-circuit current (Isc) followed by recurrent cyclical increases in Isc. The transient phase of the response was examined previously and was not investigated in these studies. Histamine (1.5-2.5 x 10(-5) M) evoked a peak increase in Isc of 177 +/- 25 microA/cm2 at intervals of 5 min for 1-2 h. The duration of each recurrent cycle averaged 2.1 +/- 0.3 min. The H2 agonist dimaprit evoked recurrent cycles that had larger amplitudes than those caused by histamine. In the presence of histamine or dimaprit, the amplitude of the first cycle of the response was always less than subsequent cycles, regardless of the initial concentration. The cyclical responses to histamine, 2-methylhistamine, or dimaprit were unaltered by the H1 blocker pyrilamine, were reduced by the H2 antagonist cimetidine, and were abolished by the neuronal blocker tetrodotoxin. Blockade of prostaglandin formation with piroxicam did not prevent the recurrent cycles. The recurrent cycles were inhibited by the chloride transport blocker bumetanide and by removal of chloride ions. Our results demonstrate that histamine mediates prolonged cyclical chloride secretion in the guinea pig distal colon by activating H2 receptors on submucosal neurons involved in regulation of epithelial chloride transport.

[Investigation of the water quality of Yalu Zangbo Jiang and the well-water of towns along it]

This article reports for the first time results of investigation on the water quality of the Yalu Zangbo Jiang and the wells-water of towns along it. It analysed such items of the water quality as pH, temperature, turbidity, total hardness, chloride, sulphate, nitrogen nitrate, fluoride, iron, manganese, zinc, copper, cadmium, lead and arsenic. The data indicated clearly that the turbidity and iron content of the river water and some of the wells were higher, but total hardness and fluoride content were lower, while other items analysed all conformed to the country's hygienic standard. Generally speaking, the hygienic standard of the water quality of the Yalu Zangbo Jiang, and the wells' water of towns along it is fairly good.

[Presence of flagellar antigenic subfactors in serotype 1 of Bacillus thuringiensis]

The strain G was isolated from a dead army worm (Leucania separata Walker) in corn field, at Hebei. It has the typical morphological characteristics of Bacillus thuringiensis. The serological analysis showed that the flagellar suspensions of the strain G was agglutinated only by the antisera against the H1 antigen and not by the antisera against the other 22 known H-antigens. The agglutination titre was 1:6,400. The flagellar suspension of the serotype 1, subsp. thuringiensis, was agglutinated by the antiserum against the strain G, with a titre of 1:12,800. However, the cross-saturation of antisera showed that there were different fractions in the H1 antigen. The H antiserum against subsp. thuringiensis still agglutinated with subsp. thuringiensis, having a titre of 1:6,400, even if it was fully saturated by strain G. When it was saturated by subsp. thuringiensis the H antiserum of strain G did not agglutinate by himself. Therefore, the H1 antigen (subsp. thuringiensis) must be divided into subfactors H1alb and strain G antigen is H1a. On the basis of this study, we propose the strain G represents the serotype H1a under the name of Bacillus thuringiensis subsp. hebeiensis.

Histamine augments colonic secretion in guinea pig distal colon

We tested the hypothesis that the role of histamine in the control of intestinal secretion is mediated by prostaglandins (PGs). The effects of histamine on ion transport were examined in muscle-stripped sheets of mucosa/submucosa set up in flux chambers. Histamine evoked a transient concentration-dependent increase in short-circuit current (Isc) that was reduced by the Cl- transport inhibitor bumetanide. Histamine also caused the release of PGE2. The Isc response to histamine was reduced by indomethacin and piroxicam, which block PG formation, but not by nordihydroguaiaretic acid, which prevents production of lipoxygenase products. 2-Methylhistamine, but not dimaprit, evoked a concentration-dependent increase in Isc. The Isc response to histamine was reduced by the H1-blocker pyrilamine, but not by the H2-antagonist cimetidine. In addition to its direct effect, histamine augmented the responses of endogenously released neurotransmitters with and without indomethacin and hexamethonium. Tetrodotoxin (TTX) reduced the Isc response to 10(-3) M histamine. In the presence of TTX, exogenous histamine amplified the responses to PGs, vasoactive intestinal polypeptide, 2-chloroadenosine, bethanechol, and carbachol. These results suggest that histamine acts at H1-receptors on cells within the gut to mediate intestinal Cl- secretion in part by releasing PGs and by augmenting the actions of endogenously released neurotransmitters. Our results indicate that histamine has a role in the regulation of colonic transport function.

Effects of tetrodotoxin on chloride secretion in rabbit distal colon: tissue and cellular studies

The effects of tetrodotoxin (TTX) were examined in muscle-stripped segments of rabbit distal colon and in cells of isolated colonic crypts. Electrical field stimulation (EFS) of the submucosa/mucosa evoked an increase in short-circuit current (ISC) that was due to an increase in chloride secretion. The EFS-evoked response was reduced 81% by 10(-7) M TTX and 30% by 5 X 10(-6) M atropine. Vasoactive intestinal peptide (VIP), carbachol, aminophylline, and 1,1-dimethyl-4-phenylpiperazinium increased ISC. Bumetanide reduced the responses to neural stimulation, aminophylline, and VIP. To determine whether TTX had direct effects on crypt epithelial cells, crypts were isolated and cells were impaled with microelectrodes. Mean resting potential (Vbl) was -67 +/- 1.1 mV (n = 63). VIP and aminophylline depolarized Vbl by 34 +/- 4.6 (n = 13) and 34 +/- 3.5 mV (n = 18), respectively. TTX had no significant effect on resting Vbl or on the responses to VIP or aminophylline. We conclude that stimulation of submucosal neurons in the rabbit distal colon evokes a TTX- and bumetanide-sensitive increase in net chloride secretion that is dependent on the release of acetylcholine and other secretory neurotransmitters. Electrophysiological studies rule out a direct effect of TTX on colonic crypt cells.

[The protective effect of selenium on acute myocardial hypoxia at high altitude]

The protective effect of selenium on acute myocardial hypoxia due to exposure to high altitude were studied by light microscope and transmission, electron microscope. The blood concentration of selenium of Wistar Rats given with sodium selenium were examined by fluorometry began from lower altitude area and were killed after reaching each correspondent elevation areas. The experiment was similar to that human 'laddering Mounting' to high altitude. The results showed that myocardial lesions were less in the animals to which sodium selenium were given than those not given, and it was not easily detected. The blood selenium concentration was significantly higher in the former than the latter (P greater than 0.01). This suggest that the selenium has unprotective effect on acute cardiac hypoxia of rats exposed to high altitude, its protective mechanism is discussed in this paper.

Complete sequence of the lamprey fibrinogen alpha chain

The complete amino acid sequence of the lamprey fibrinogen alpha chain has been determined by a combination of peptide sequencing and cDNA and genomic cloning. The chain, which has an apparent molecular weight by dodecyl sulfate-polyacrylamide gel electrophoresis of ca. 100,000, is composed of 961 amino acid residues and has a calculated molecular weight of 96,722. It is distinguished by a large number of 18-residue repeats in a region where mammalian fibrinogens have 13-residue repeats. The data are in accord with our previous finding that the lamprey alpha chain has a distinctive amino acid composition, almost half the residues being glycine, serine, or threonine. The chain differs from mammalian alpha chains in that there are no cysteines in the carboxy-terminal half, and thus no intrachain loop, nor are there any RGD sequences in the lamprey alpha chain. Taken together with previous data on the sequences of the beta and gamma chains, the findings bear significantly on our understanding of fibrin formation. The alpha chain also provides an interesting case of structural convergence during evolution.

Effects of aminoglutethimide on hypothalamic-pituitary-adrenal functions

This study was performed on four groups of subjects, including 10 patients with Cushing's disease, 10 patients with simple obesity, 8 patients with hypopituitarism and 13 normal subjects. The study was conducted by measuring the sequential changes of plasma ACTH, serum cortisol, 24-h UFC, 24-h 17 KS and 24-h 17 KGS following aminoglutethimide (AG) administration. The results suggest that normal subjects showed sequential changes of hypothalamic-pituitary-adrenal hormone concentrations with normal feedback regulation of the axis following AG administration. Patients with Cushing's disease had obvious autonomy in the production of ACTH from the pituitary. Patients with simple obesity might display abnormality to some degree in the production from the pituitary. Patients with hypopituitarism lost the capacity of ACTH production in various degrees because of pituitary lesions.

[Clinical, immunophenotypic and cell cyclic analysis in chronic lymphocytic leukemia]

15 cases of chronic lymphocytic leukemia (CLL) were immunophenotyped with a panel of monoclonal antibodies. 13 cases were B-CLL, which was characterized by CD20+, HLA-Dr+, SmIg+ and CD5+/Em+. 2 cases were T-CLL, one with Ts phenotype and HLA-Dr+ T-Cll in the other. The ratio of G0 + G1 cells in bone marrow of CLL was 91.1 +/- 2.3% (76.0 +/- 5.1% in controls), while S + G2M cells was 8.9 +/- 2.3% (23.9 +/- 5.1% in controls). The ratios of various cyclic cells were similar in bone marrow and in peripheral blood. Prolymphocytoid transformation developed in the late stage in 3 CLL patients. The clinical course, cytochemistry and immunologic changes in CLL were also analysed.

Evidence for laser cooling in a magnesium atomic beam

Laser cooling in a Mg atomic beam is reported for the first time to our knowledge. Previous cooling experiments were performed by using visible or infrared lasers. The Mg atoms were cooled by using an intracavity frequency-doubled dye laser at 285 nm to reach the resonant (1)S(0)-(1)P(1) transition. Evidence of laser cooling was obtained even with the limited available laser power ( approximately 1-2 mW).

Primary study of attenuated live hepatitis A vaccine (H2 strain) in humans

Strain H2, an attenuated live hepatitis A virus (HAV), was derived from the fecal specimen of a patient with hepatitis A in Hangzhou, China. After isolation and passage in a culture of newborn monkey kidney cells, adaptation to grow in human lung diploid cells (KMB17), and serial passage at a low temperature (32 degrees C) in KMB17 cells, this strain became the master seed virus for H2-strain vaccine. Twelve human volunteers received the experimental vaccine subcutaneously and were closely observed for 20 w. None of the subjects developed any local or systemic reactions, and there were no elevations of serum glutamic-pyruvic transaminase, type 5 isoenzyme of lactate dehydrogenase, or isocitrate dehydrogenase. Seroconversion occurred in all subjects at a mean time of 3 w after inoculation. ELISA competitive test for titer of antibody to HAV showed values ranging from 1:2 to 1:8 with a geometric mean titer of 1:3.48 at 20 w after inoculation. No marked decrease in titer of HAV antibody was found in the subjects tested at 1 y. These antibodies were proved to be neutralizing antibodies.

[Studies on the quality of Gastrodia elata Bl. cultivated with various kinds of fungus-growing materials]

In this article, the chemical compositions of 14 kinds of fungus-growing materials, and their corresponding rhizomorph and G. elata are analysed with thin layer chromatography. The properties of each G. elata and the contents of gastrodin in each G. elata are also analysed. The result shows that their properties and chemical compositions are similar, thus providing a basis for a larger choice of fungus-growing materials in cultivating G. elata.

[Toxicity experiment on Sargassum, radix Knoxiae, radix Ransul and flos Genkwa against radix Glycyrrhizae in the antagonism of 18 Chinese drugs]

In order to further look into the cause of the antagonisms in the 18 Chinese medicinal herbs, stimulation and toxicity experiments, with five Chinese medicinal herbs (Sargassum Radix Knoxiae, Radix Kansul and Flos Genkwa against Radix Glycyrrhiza) as a group, were done in healthy rats and rabbits.