Factors accounting for different responses of pulmonary and cerebral vessels to hypoxia

The roles of sympathicus, sensory neuropeptides (SNP), cyclooxygenase metabolites (COX-M), lipoxygenase metabolites (LOX-M), endothelium derived relaxing factor (EDRF), reactive oxygen (ROS) and potassium channels (PC) in the hypoxic pulmonary vasoconstriction (HPV) and hypoxic cerebral vasodilation (HCVD) were investigated in intact rats, rabbits and dogs. The results showed that during hypoxia, the excitation of sympathicus caused a constriction of both pulmonary and cerebral vessels, while SNP, EDRF and the opening of voltage sensitive PC caused the dilation of both of them; LOX-M mediated HPV and HCVD, COX-M might serve as their modulators; the blockade of ATP sensitive PC induced by hypoxia mediated HPV, but had no effect on HCVD; the reduction of O2-. in the lung might potentiate HPV, however, O2-. remained unchanged in brain during hypoxia. It is suggested that the alterations of LOX-M, ROS and the ATP sensitive PC are the factors accounting for the difference in the response of pulmonary and cerebral vessels to hypoxia.

[The effect of intra-aortic balloon pumping in case of left main coronary artery stenosis]

In order to improve perfusion of coronary artery in case of coronary artery stenosis, effect of intra-aortic balloon pumping (IABP) on coronary blood flow (CBF) was investigated. To this end hemodynamic parameters of heart functions with and without stenosis were analysed under IABP. Hemodynamic effect of IABP was obviously influenced by the coronary artery stenosis.

Comparison of systemic and direct intrarenal angiotensin II blockade on sodium excretion in rats

To dissociate the renal effects from the systemic effects of angiotensin II blockade, the present study was designed to determine the effects of systemic and renal interstitial infusion of the specific angiotensin II (ANG II) receptor antagonist, losartan, on blood pressure and sodium excretion in rats fed a low-, normal, or high-sodium diet. Fractional sodium excretion (FENa) and mean arterial pressure (MAP) were measured in rats before and during systemic infusion of losartan (10 mg/kg) or renal interstitial infusion of losartan (3 mg/kg) by means of a chronically implanted matrix. In rats fed a low- or normal sodium diet, systemic infusion of losartan markedly decreased MAP (delta -21 +/- 2, delta -10 +/- 2 mmHg, respectively; P < 0.05) with an accompanying fall in FENa (delta -0.10 +/- 0.05, delta -0.91 +/- 0.40%, respectively; P < 0.05). In contrast, preferential blockade of renal ANG II with renal interstitial losartan infusion resulted in an increase in FENa (delta 0.13 +/- 0.04, delta 0.95 +/- 0.45%, respectively; P < 0.05) and no significant change in MAP. In rats fed a high-sodium diet, both systemic and renal interstitial infusion of losartan increased FENa (delta 1.90 +/- 0.26, delta 1.40 +/- 0.56%, respectively; P < 0.05). Although systemic infusion of losartan decreased MAP (delta -4.4 +/- 0.6 mmHg, P < 0.05) in rats fed a high-sodium diet, the reduction in MAP was much less than that in rats fed a low- and normal sodium diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of a polymer-enzyme immunoassay method and its application

Both poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide)-antibody (PINP-Ab)-labelled enzyme adhered quickly and tightly to cellulose acetate/nitrate membrane either below (less efficiently) or above (more efficiently) the lower critical solution temperature, and the retention of PINP-Ab on the membrane increased over 30-fold when compared with the unconjugated Ab. These characteristics were used to develop a novel polymer-enzyme-linked immunoassay method: homogeneous antigen-antibody immune-complexation reaction and a heterogeneous separation process. By using a simple horseradish-peroxidase-labelled antibody as a probe, we applied this method to the detection of human serum hepatitis B surface antigen (HBsAg). This immunoassay system can detect as little as 1 ng/ml of HBsAg. The advantages of this method are: (a) fast homogeneous immune complexation; (b) a rapid heterogeneous separation process; (c) high sensitivity; and (d) low non-specific background.

Changes of cellular morphology and nuclear DNA content in different nasopharyngeal epithelium from different patients

Cellular morphology and nuclear DNA content were measured with point-counting technique and flow cytometry (FCM) respectively in normal nasopharyngeal epithelium (NE), tissue adjacent to carcinoma (ATC) and nasopharyngeal carcinoma (NPC). The results showed that all 20 patients with NE showed diploid, whereas 38 (38%) of 101 patients with NPC, 7 (58%) of 12 patients with recurrent NPC, 6 (30%) of 20 patients with ATC and 2 (33%) of 6 patients with NE positive to EBVCA-IgA test showed nondiploid. A total of 19 morphometric parameters of the cell were measured and calculated. The results showed that with malignant transformation of NE, most of the cellular morphometric parameters gradually increased in numerical values while no marked difference was shown between normal NE and simple hyperplasia or metaplasia in terms of cytomorphometric characteristics. Most of the parameters in dysplasia changed significantly as compared with those normal NE, simple hyperplasia or metaplasia and NPC groups. Cytomorphometric analysis seems to give strong support to the concept that dysplasia is among the transitional stages of disease process between normal NE and NPC. Our results show that morphometric analysis and FCM may offer valuable and objective criteria in the early diagnosis of NPC and premalignant disease.

Predictors for failure of Pneumocystis carinii pneumonia prophylaxis. Multicenter AIDS Cohort Study

OBJECTIVE

To identify clinical and epidemiological factors associated with failure of Pneumocystis carinii pneumonia (PCP) prophylaxis in those receiving primary and secondary prophylaxis.

DESIGN

Longitudinal cohort study of participants infected with human immunodeficiency virus type 1 in the Multicenter AIDS Cohort Study who used PCP prophylaxis regimens after their T-helper lymphocyte counts had decreased to less than 0.200 x 10(9)/L (200/microL).

MAIN OUTCOME MEASURE

Occurrence or recurrence of PCP.

RESULTS

A total of 476 participants reported taking one or more of the following regimens: trimethoprim-sulfamethoxazole (TMP-SMX), dapsone, and/or aerosolized pentamidine--367 as primary prophylaxis and 109 as secondary prophylaxis after a previous episode of PCP. A total of 92 (20%) developed PCP despite prophylaxis. The mean failure rates per person-year of follow-up were 16.0% for those receiving primary prophylaxis and 12.1% for those receiving secondary prophylaxis (P = .19). Median times to death after initiation of primary or secondary prophylaxis were 2.0 and 1.2 years, respectively. The main predictor for failure of PCP prophylaxis was profound T-helper lymphocytopenia; 86% of failures occurred after T-helper cell counts decreased to less than 0.075 x 10(9)/L and 76% occurred after counts decreased to less than 0.050 x 10(9)/L. In multivariate time-dependent analysis, when compared with counts between 0.100 x 10(9)/L and 0.200 x 10(9)/L, the risk ratio for failure with counts less than 0.050 x 10(9)/L was 2.90 (P < .001). Once T-helper cell counts were considered, fever was the only other health status indicator that predicted subsequent PCP (ie, a time-dependent risk ratio of 2.22; P = .01). Use of TMP-SMX as the prophylaxis regimen was protective but did not eliminate failure (ie, a time-dependent risk ratio of 0.55; P = .03).

CONCLUSIONS

These findings strongly support identifying improved methods of PCP prophylaxis once T-helper cell counts decrease to less than 0.075 x 10(9)/L or 0.100 x 10(9)/L. Given this severe degree of immunosuppression, an inherently more effective regimen against P carinii is required.

High-specificity neurological localization using a connectionist model

Most previous connectionist models for diagnosis have been developed using error backpropagation. While these systems function reasonably well, they have been limited by their need for a large database of test cases, to situations where a single disorder is present, and by the large number of connections required between fully-connected sets of processing units. Here we describe a recently developed connectionist model that overcomes these limitations. This approach can reuse existing causal knowledge bases, works well in situations where multiple disorders can occur simultaneously, and does not require fully-connected sets of processing units. We demonstrate that the accuracy of this model is comparable to that of more conventional AI programs using the same knowledge base in determining precisely the site of brain damage in a group of 50 stroke patients. These results support the conclusion that connectionist models can effectively use pre-existing causal knowledge bases from AI systems, and that they can function accurately when handling actual clinical problems.

Glycine and GABAA antagonists reduce the inhibition of primate spinothalamic tract neurons produced by stimulation in periaqueductal gray

Amino acids are demonstrated to be important neurotransmitters mediating the inhibitory transmission from nucleus raphe magnus to spinal nociceptive dorsal horn neurons. In this study, the role of glycine and GABA in the inhibitory processes evoked by stimulation in periaqueductal gray (PAG) of responses of primate spinothalamic tract (STT) neurons to cutaneous mechanical and thermal stimuli was investigated by examining the effects of strychnine and bicuculline, antagonists of glycine and GABAA receptors, respectively, introduced into the dorsal horn through a microdialysis fiber. The inhibitory effects of iontophoretic application of glycine and GABAA agonists on STT cell activity evoked by noxious mechanical stimulation of the skin were selectively blocked by their specific antagonist, strychnine or bicuculline, infused into the dorsal horn. Similarly, intra-spinal application of strychnine or bicuculline resulted in a significant reduction in the PAG stimulation-induced inhibition of responses of STT cells to cutaneous stimuli. This reduction was mainly on the PAG-induced inhibition of the responses to noxious mechanical stimuli. Our results suggest that glycinergic and GABAergic inhibitory interneurons in the spinal cord dorsal horn synapsing on STT cells are activated during stimulation in PAG and contribute to descending antinociceptive actions.

Markers of thromboembolization in a bovine ex vivo left ventricular assist device model

The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricular assist device (LVAD) model in calves. Each of eight calves received a series of three LVADs, each operating for 24 hr. Blood microemboli were measured directly by a laser (624 nm and 828 nm) light scattering microemboli detection (LSMD) system through the LVAD outflow cannula and by constant pressure filtration (CPF) of blood samples from the LVAD outflow cannula. Hematologic parameters were also measured. After LVAD removal, perivalvular thrombi were evaluated using polar coordinate mapping. The average LSMD and CPF results correlated. For example, in one series of three calves, one ventricle exhibited significantly greater thrombogenesis than did the other ventricles, as indicated by both the LSMD and CPF results. In a series of five calves, one calf developed an abnormally high activated thromboplastin time (APTT), even in the absence of heparin. For two of the three ventricles tested in that calf, microemboli concentration (CPF), Factor XII activity, level of fibrin degradation products (FDP), and accumulated thrombus were significantly lower than for the other calves. The whole blood viscosity (WBV, at 230 s-1) in this calf also decreased to lower values than were seen with the other calves.

Hyperglycemia delays rostral initiation sites during neural tube closure

Neural tube defects contribute greatly to perinatal loss, physical handicap, mental retardation and other developmental defects, yet the mechanisms through which they occur are poorly understood. One hindrance to the study of these defects at the cellular and molecular levels is the low frequency with which they arise in susceptible animals. The present study utilizes a culture system for the study of rodent exencephaly, an animal model of human anencephaly, in which a high frequency of affected animals are obtained by culture in hyperglycemic rat serum. Rat embryos were dissected at day 9.5 from timed-pregnant Sprague-Dawley dams and cultured under standard conditions developed by New [Biol. Rev. (1978) 53,81-122]. Embryos cultured under elevated glucose conditions are able to close the caudal neural tube with the failure of neural tube closure limited to the rostral neuralepithelium. In this report we present the novel finding that, although at the end of culture frequently only the hindbrain region remains open, the normal sequence of events expected during rostral closure anterior to the hindbrain is markedly delayed. In embryos cultured in hyperglycemic serum, both rostral initiation sites II and III are significantly delayed. The degree of delay increases with increasing glucose concentration in the culture medium. These studies support the use of this defined in vitro model of anencephaly for studies of the molecular and cellular bases underlying the failure of hindbrain closure and demonstrate that sufficient numbers of affected animals can be produced to obtain significant results.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hypertension inducing cerebrovascular damage and effecting on cerebral infarction]

Cerebrovascular damage of renovascular hypertensive rats (RHR) was observed under light microscope and electron microscope, and the cerebral collateral vessels of RHR were observed with vascular casts. In focal cerebral ischemia of RHR, the infarct volume was measured by TTC staining in combination with computer image processing and analysis. When hypertension persisting longer, there were hyalinosis in small arterial walls, luminal narrowing and basement membrane thickening in capillaries, decreased collateral vessels, and occluded microvessels. In cerebral ischemia, the infarct volume was large and could not be improved. The results demonstrated that the key to prevent stroke is to prevent and treat hypertension as early as possible.

[Study on endocytosis and nuclear accumulation of epidermal growth factor (EGF) in normal C3H mouse fibroblast cells C3H10 T1/2C18 and 3H-TdR transformed counterpart cells]

In this study, we investigated endocytosis and nuclear accumulation of epidermal growth factor (EGF) in normal C3H mouse embryo fibroblast cells C3H10 T1/2 C18 (designated NC3H10) and 3H-TdR transformed counterpart cells (designated TC3H10). The results revealed that 125I-labelled EGF bound to the receptor on the cell surface of the two cell lines was subsequently endocytosed and translocated from the cell membrane to the nucleus, where it progressively accumulated. NC3H10 showed more EGF accumulation in nucleus than TC3H10 (p < 0.05). SDS-polyacrylamide gel electrophoresis revealed that the endocytosed 125I-EGF associated with the nucleus was intact, with negligible breakdown products present. The nuclear accumulation of intact EGF in the mentioned cell lines exposed to ammonium chloride (a lysosomal inhibitor) was higher than the control (p < 0.05). These results suggested that receptor-mediated endocytosis and nuclear accumulation of EGF may play an important role in mediation some of the action of EGF.

[Preliminary mechanism studies of siwenmycin on the inhibition of nucleic acid syntheses]

Siwenmycin, isolated from a streptomyces culture, is a new member of aclacinomycin analogues. It exhibited a remarkable inhibitory effect on the biosynthesis of DNA and RNA in vivo. In order to recognize the mechanism of the inhibitions, the reactions of siwenmycin to DNA template, DNA polymerase I and RNA polymerase were studied. Experimental results showed that siwenmycin could intercalate DNA, but it did not inhibit DNA polymerase I-mediated DNA repair replication and T7RNA polymerase-mediated DNA transcription. This indicates that siwenmycin is not a damage to the DNA template function, nor will it inhibit DNA polymerase I and T7RNA polymerase, though it can intercalate DNA.

[Electrophoretic analysis of isoenzyme and protein patterns of Romanomermis yunanensis and R. culicivorax (Nematoda:Mermithidae)]

Isoenzyme electrophoretic patterns of lactate dehydrogenase (LDH), malate dehydrogenase (MDH), esterase (EST) and peroxidase (PO) of post-parasitic juveniles and adults of Romanomermis yunanensis and R. culicivorax were analysed by disc electrophoresis, respectively. The protein patterns of the two species of Romanomermis were compared by vertical slab SDS polyacrylamide gel electrophoresis. The results showed marked differences in isoenzyme patterns (number of bands and/or Rf) of LDH and MDH between the two species of Romanomermis, but the similar positions of isoenzyme bands denoted a certain genetic relationship between them. No band was found in the isoenzyme patterns of PO and EST. Distinct differences in protein pattern were observed between the two species of Romanomermis, but some common bands in pattern reflected the phylogenetic relationships of these species. The differences of isoenzyme and protein patterns observed in this study have provided the reason for identifying and differentiating the two species of Romanomermis at the molecular level.

Simple Systems That Exhibit Self-Directed Replication

Biological experience and intuition suggest that self-replication is an inherently complex phenomenon, and early cellular automata models support that conception. More recently, simpler computational models of self-directed replication called sheathed loops have been developed. It is shown here that "unsheathing" these structures and altering certain assumptions about the symmetry of their components leads to a family of nontrivial self-replicating structures, some substantially smaller and simpler than those previously reported. The dependence of replication time and transition function complexity on initial structure size, cell state symmetry, and neighborhood are examined. These results support the view that self-replication is not an inherently complex phenomenon but rather an emergent property arising from local interactions in systems that can be much simpler than is generally believed.

Minimizing complexity in cellular automata models of self-replication

Understanding self-replication from an information processing perspective is important because, among other things, it can shed light on molecular mechanisms of biological reproduction and on prebiotic chemical evolution. Intuition, biological knowledge, and early computational models of self-replication all suggested that self-replication is an inherently complex process. In this paper we describe recent computational studies that challenge this viewpoint. We summarize our recent work with cellular automata models of simple yet non-trivial self-replicating structures called unsheathed loops. For example, one unsheathed loop consists of only six components and requires only 20 rules to specify the local intercomponent interactions needed to bring about replication. The implication of this work is that, when viewed as an emergent property of numerous local, concurrent interactions between components, self-replicating systems can be substantially simpler than is generally recognized.

Synergistic and antagonistic effects on genotoxicity of chemicals commonly found in hazardous waste sites

Synergistic and antagonistic effects on genotoxicity of mixtures of four chemicals; i.e., lead tetraacetate (LTA), arsenic trioxide (ATO), dieldrin (DED), and tetrachloroethylene (TCE), were evaluated by the Tradescantia-micronucleus (Trad-MCN) assay. The chemicals were mixed in ratios of 1:1, 1:2 and 2:1 for mixtures of two chemicals and 1:1:1 each for three chemicals. The concentration of stock solution of these chemicals was around the minimum effective dose (MED) or below the MED for these chemicals as reported by Sandhu et al. (1989). Treatments were applied to plant cuttings by hydroponic uptake of the mixed solutions through the stems of the plant for 30 h followed by fixation of the flower buds in aceto-alcohol (1:3 ratio) without a recovery period. Microslides were prepared for scoring MCN frequencies. Results of two series of repeated experiments indicated that all mixtures of LTA/ATO exhibited antagonistic effects. On the other hand, all mixtures of TCE and DED exhibited synergistic effect. These data indicate that for evaluating biological hazards at chemical waste sites, it is prudent to evaluate the genotoxicity of complex chemical mixtures as these exist in nature because the biological effects based on evaluating individual chemicals may not be true predictors of the interactive effects of the pollutants.

[Chemical constituents of Ipomola batatas Lam]

Three chemical compounds isolated from the leaves and stems of Ipomoea batatas were identified as fumaric acid, succinic acid and 7,3',4'-trimethylquercetin by chemical and spectroscopic analysis. In this paper, an analysis of the amino-acids of Ipomoea batatas is also reported.

Replacement of cholesterol gallstones by murideoxycholyl taurine gallstones in prairie dogs fed murideoxycholic acid

The effect of two hydrophilic bile acids, murideoxycholic acid (3 alpha,6 beta-dihydroxy-5 beta-cholanoic acid) and ursodeoxycholic acid, on cholesterol and bile acid metabolism and hepatic pathology and gallstone composition was studied in the prairie dog. Cholesterol gallstones were induced by feeding a diet containing 1.2% cholesterol for 75 days. The animals were divided into six groups, and gallstone regression was studied as follows: groups 2 and 5, chow plus 0.2% cholesterol; groups 3 and 6, chow plus 0.2% cholesterol plus 0.15% ursodeoxycholic acid; groups 4 and 7, chow plus 0.2% cholesterol plus 0.15% murideoxycholic acid. Animals in groups 2 to 4 were killed after an additional 6 wk; animals in groups 5 to 7 were killed after an additional 12 wk. Gallstone dissolution did not occur in any group. The gallstones in groups 2, 3, 5 and 6 were typical cholesterol aggregates, as determined by polarized light microscopy and Fourier transform infrared spectrometry. The gallstones of the murideoxycholic acid group were large, solitary, dark stones that appeared radiopaque under 22 kVp x-ray examination. Scanning electron microscopy showed that in these stones the cholesterol crystals had been replaced by an amorphous material, both within the stone and on the stone surface. Chemical analysis indicated that at the end of 12 wk the calcium/sodium salt of the taurine conjugate of murideoxycholic acid (murideoxycholyl taurine) comprised 70% of the stones; protein, cholesterol and small amounts of other bile salts were also present. In vitro studies confirmed the insolubility of the sodium and calcium salts of murideoxycholyl taurine. These studies indicate that the hydrophilic bile acids, murideoxycholic acid and ursodeoxycholic acid, did not achieve gallstone dissolution under the conditions used. In the animals fed murideoxycholic acid, an insoluble calcium salt of murideoxycholyl taurine replaced cholesterol as the major constituent of gallbladder stones. This is the first example of an insoluble dihydroxy taurine-conjugated bile acid; administration of the unconjugated bile acid induced precipitation of a kind of gallstone not previously reported. The final result was transformation of cholesterol stones to bile salt stones.

Bioartificial thyroid. The in vitro culture of microencapsulated rabbit thyroid tissue

A new technique of encapsulating thyroid tissue with an artificial membrane for protection against immune attack is reported. The membrane was made of calcium alginate and a poly-L-lysin coating. The membrane prevents the diffusion of large molecules such as hemoglobin but freely permits the passage of smaller molecules such as T4 and culture medium 1640. Because larger molecules are barred, the contents of the microcapsules are safe from immune system rejection. In vitro cultured, microencapsulated rabbit thyroid tissue secreted T3 and T4, achieving a concentration of 8.68 +/- 2.93 nmol/L and 245.23 +/- 124.87 nmol/L, after 3 days; this level remained steady for 6 to 9 days of incubation. These microcapsules show promise as a treatment modality and as a possible solution to the problem of immuno-isolation.

Clinical observations on acupuncture treatment of peripheral facial paralysis aided by infra-red thermography--a preliminary report

We have carried out clinical observations on 34 patients with peripheral facial paralysis treated by acupuncture therapy prescribed according to selection of treatment regimen on the basis of facial thermogram and temperature. A comparison was made with a control group of 97 patients who received conventional acupuncture therapy only. It was found that 1) The cure rate in the group of selecting acupoints by thermogram (hereinafter referred to as the thermography--aided treatment group) was 67.65%, with a marked improvement rate of 26.40%; while the cure rate of the conventional acupuncture treatment group (hereinafter called the conventional treatment group) was 46.39%, the marked improvement rate being 29.90%, indicating a significant difference in therapeutic efficacy between the two groups (P less than 0.02). 2) The average duration of acupuncture therapy for the thermography aided treatment group was 6.02 weeks, whereas that for the conventional treatment group, 24 weeks. There was also a significant difference between the two groups (P less than 0.01). And 3) During the entire therapeutic course, 25.2 sessions of treatment were given on the average in the thermography--aided treatment group, and 78.8 sessions in the conventional treatment group, showing a very significant difference (P less than 0.001). The present thermography--aided method exhibits advantages over the conventional one in enhancing the cure rate and shortening the duration of treatment, which is worthy to be popularized in clinical practice. And it is also of certain significance in standardization and scientification of acupuncture therapy.

Multivariate comparison of the forelimb between stump-tailed and rhesus macaques

Rhesus macaques and stump-tailed macaques are sympatric in western Yunnan (China), coexisting or occupying habitats that show little difference. This paper tests hypotheses based on theoretical expectation from the differing biomechanical demands of terrestrial and arboreal quadrupedalism in stump-tailed macaques and rhesus macaques, respectively. Individuals of these two macaque taxa were markedly separated by the first two principal components and discriminant analyses based on 18 variables of the upper limb. The rhesus macaques appear to be more adapted for arboreal quadruped habits because of elongation of the clavicle and forearm, a larger humeral head and greater midshaft sagittal diameters of the radius and ulna.

Tunicamycin-resistant variants from five species of Leishmania contain amplified DNA in extrachromosomal circles of different sizes with a transcriptionally active homologous region

Twelve independent variants were selected from five species of Leishmania for resistance to tunicamycin by exposure of cultured promastigotes to increasing concentrations of this antibiotic, an inhibitor of the microsomal N-acetylglucosamine-1-phosphate transferase in the dolichol pathway of N-glycosylation. All variants obtained from all species, as found previously with Leishmania amazonensis, contain amplified chromosomal DNA exclusively as extrachromosomal circles. These circular amplicons hybridize with amplified DNAs cloned previously from tunicamycin-resistant Leishmania amazonensis, but not with those from Leishmania resistant to other drugs. The amplicons from tunicamycin-resistant cells vary with different species in size from 30 to 70 kb, but all share a homologous region of 20 kb. Multiple independent transcripts are overexpressed from this region. Elevation of the microsomal glycosyltransferase activity is demonstrated in these variants from representative species. The results thus provide further evidence that this enzyme is overexpressed due to amplification of the gene in these cells. The consistent observation of this event in all cases studied also suggests that this is the predominant, if not the only mechanism of tunicamycin resistance in Leishmania.

Ocular pulse amplitude in myopia

We studied the ocular pulse amplitude of myopic patients by using Alcon Pneumotonography. One hundred and eighty-eight cases (376 eyes) were enrolled in this study. The results revealed that the higher the myopia the lower the ocular pulse amplitude. The pulse amplitude has high correlation with refractive error and axial length, but poor correlation with scleral rigidity, intraocular pressure and corneal curvature. As the ocular pulse amplitude is generated by the choroidal blood flow, these results may reflect circulatory disturbance in the development of myopia.

Dialyzability and binding of digoxin-like immunoreactive factors (DLIF) with serum macromolecules in uremic patients on hemodialysis

Digoxin-Like Immunoreactive Factors (DLIF) which cross-react with antidigoxin antibodies are present in elevated concentrations in patients on hemodialysis, uremia, hypertensives, liver failure, pre-eclampsia and premature birth. DLIF may have a potential role as a natriuretic hormone with a speculated low molecular weight (less than 1000). We studied the dialyzability and bindings of DLIF with serum components in hemodialysis patients. We analyzed DLIF concentrations in sera and protein free ultrafiltrates of 31 patients and 22 normal volunteers using a fluorescence polarization assay for digoxin. The DLIF concentrations were expressed as nmol/L Digoxin Equivalent. The gel filtration analysis was done using three different Bio-Gel columns with molecular weight cut-offs of 10,000, 20,000 and 40,000. Molecules with lower molecular weight than cut-off were absorbed in the column. Only 3 out of 22 normal volunteers (13.6%) showed measurable DLIF. However 23 out of 31 patients (74.2%) showed measurable DLIF. The concentrations of DLIF were significantly higher in patients with renal failure on hemodialysis (P less than 0.05) by both chi-squared and Fisher's exact test. We observed no statistically significant difference in the concentrations of DLIF in pre and post-dialysis sera, indicating that DLIF were not filtered during hemodialysis. We observed no DLIF activity in the protein free ultrafiltrates of any DLIF positive sera (patients and normal volunteers), indicating that unlike digoxin (where we observed 70-80% of total digoxin concentrations in ultrafiltrates), DLIF were strongly bound to serum components. With Bio-Gel filtration experiments (five different serum pools), we recovered all DLIF activities in the fraction equivalent to the void volume of the column with Bio-Gel P6 and P10 columns, indicating that DLIF were almost completely bound to serum components with molecular weight greater than 20,000. On the other hand, we recovered no DLIF activities in the void volume when the same serum pools were passed through the Bio-Gel P30 column, indicating that DLIF were strongly bound to serum macromolecules with molecular weight less than 40,000. In sharp contrast, when serum containing digoxin was subjected to the same series of experiments, we recovered only 20-30% of digoxin concentrations in void volume with all three columns as expected since digoxin is only 25% bound to albumin (MW 67,000).

An immunopathologic study of retinoblastoma protein

We investigated the immunoreactivity of the retinoblastoma protein in eight retinoblastoma tumors of different stages of differentiation. All undifferentiated tumor cells failed to show immunoreactivity. In one patient, who had a family history of retinoblastoma and had been treated by radiation, the tumor had a large area of undifferentiated cells and small independent retinocytomas. The tumor cells in the retinocytoma and the cone cells in the adjacent retina, but not the undifferentiated tumor cells, showed positive staining with two anti-Rb antibodies. The immunoreactivity may be related to radiation or differentiation of retinoblastoma and cone cells.

Clastogenicity evaluation of seven chemicals commonly found at hazardous industrial waste sites

7 chemicals commonly found at the industrial waste sites were tested with the Tradescantia-Micronucleus (Trad-MCN) assay to evaluate their clastogenic potential. Chemicals selected from the US EPA Superfund Priority 1 list were: aldrin, arsenic trioxide, 1,2-benz[a, h]anthracene, dieldrin, heptachlor, lead tetraacetate and tetrachloroethylene. Results of repeated tests for clastogenicity yielded the minimum effective dose (MED) for clastogenicity of 0.44 ppm for lead tetraacetate, 1.88 ppm for heptaclor, 3.81 ppm for dieldrin and arsenic trioxide and 1,2-benz[a, h]anthracene yielded positive responses at the MED of 3.96 ppm and 12.50 ppm respectively. Aldrin and tetrachloroethylene were considered to be immiscible with water, and the tests yielded negative responses. Tetrachloroethylene in gaseous state was also used to treat the flower buds. Results of tetrachloroethylene vapor phase treatment yielded a positive response at the MED of 30 ppm/min after a 2-h exposure. 5 chemicals determined to be clastogens by this test were ranked according to their MED in the descending order of potency as follows: lead tetraacetate, heptachlor, dieldrin, arsenic trioxide and 1,2-benz[a, h]anthracene. Results of this study indicate that the Trad-MCN bioassay could be effectively utilized for assessing the potential clastogenicity of the chemicals commonly found at the industrial hazardous waste sites.

Clinical observations on occlusion myopia

The authors studied the refractive errors and axial lengths on thirty patients. A retrospective analysis suggests some degree of monocular vision deprivation early in life. Axial myopia was found in most of the cases, indicating that emmetropization is a vision-dependent phenomenon. But, some exceptions were found, supporting the concept that multiple factors are involved in the pathogenesis of myopia.

Enkephalin fibers synapse on cholinergic neurons in the rat sacral intermediolateral nucleus: a double-immunostaining at the light and electron microscopic levels

Relationships between leucine-enkephalin fibers and cholinergic neurons in the rat sacral intermediolateral nucleus were examined by light and electron microscopy using double-immunostaining method. Cholinergic neurons in the sacral intermediolateral nucleus were labeled by a rat-mouse monoclonal antibody to choline acetyltransferase and stained bluish green with 5-bromo-4-chloro-3-indolyl-beta-D- galactoside reaction products using beta-galactosidase as a marker. On the same sections, leucine-enkephalin fibers were labeled by a rabbit polyclonal antiserum to leucine-enkephalin and stained brown by diaminobenzidine reaction products using peroxidase as a marker. After embedding in Epon, the sections were examined in light and electron microscopes. In the light microscope, choline acetyltransferase-like immunoreactive cells were seen in the sacral intermediolateral nucleus. In the same region, leucine-enkephalin-like immunoreactive cells. In the electron microscope, 5-bromo-4-chloro-3-indolyl-beta-D-galactoside reaction products were in the form of coarse electron dense deposits in the choline acetyltransferase-like immunoreactive structures and could be distinguished from the much finer grained diaminobenzidine reaction products. Choline acetyltransferase-like immunoreactive neurons received synaptic inputs from leucine-enkephalin fibers-like immunoreactive terminals. These findings suggest that leucine-enkephalin fibers may affect the activity of cholinergic parasympathetic preganglionic neurons.

Direct adrenergic inputs to sacral autonomic neurons: using a double-immunostaining method at the light and electron microscopic levels

Relationships between adrenergic fibers and cholinergic neurons were examined in the rat sacral intermediolateral nucleus using a double-immunostaining method at light and electron microscopic levels. Adrenergic fibers were immunohistochemically stained brown by peroxidase reaction, and cholinergic neurons in the same sections were stained bluish green by beta-galactosidase reaction. In the light microscope, many cholinergic neurons were seen in the intermediolateral nucleus and some of them were surrounded by adrenergic fibers. In the electron microscope, adrenergic fibers made synapses with the cholinergic neurons in the intermediolateral nucleus. These results suggest that adrenergic fibers directly influence the activity of the sacral parasympathetic preganglionic neurons.