[Observation on parasite density in the early stage of vivax malaria]

Thirty-eight cases were artificially infected with local Plasmodium vivax sporozoites and experienced onsets of acute attacks after a short incubation period. The parasite densities upon the patent of malaria parasites in the peripheral blood and the primary clinical onset were 0.2-1.6 and 0.6-4 040/microliters, respectively. Such significant difference in parasitaemia level seems to be closely related to the interval between the initial parasitaemia and the first onset, as indicated by the fact that for the majority of cases, the earlier the appearance of clinical attack after sporozoite inoculation, the lower the parasite density at the beginning of the patent period, while primary onsets of later occurrence, in those with higher initial parasitemia. The biological and epidemiological significance of the evidence was discussed.

Life stress, social support, and problem-solving skills predictive of depressive symptoms, hopelessness, and suicide ideation in an Asian student population: a test of a model

The present study tested both a stress-problem-solving model and a stress-social support model in the etiology of depressive symptoms, hopelessness, and suicide ideation for a group of Asian international students in the United States. Problem-solving skills and social support were hypothesized as two mediators between life stress and depressive symptoms, hopelessness, and suicide ideation. The results from a series of stepwise regression analyses and a path analysis support the hypotheses, indicating that these models generalized to a sample of Asian international students. The roles of social support and problem-solving skills in depressive symptoms and hopelessness are discussed. The results also suggest that hopelessness may serve as a cognitive factor directly affecting depressive symptoms and indirectly affecting suicide ideation.

Dietary fish oil supplementation attenuates myocardial dysfunction and injury caused by global ischemia and reperfusion in isolated rat hearts

To determine the effect of dietary fish oil supplementation on myocardial dysfunction following ischemia-reperfusion, independent of plasma and blood cells, Sprague-Dawley rats were fed fish oil-rich nonpurified diet or butter-enriched diet for 5 d. Myocardial content of long-chain and (n-3) polyunsaturated fatty acids was greater in the fish oil-fed rats (P < 0.01), whereas (n-6) fatty acid content was lower compared with controls (P < 0.01). Platelet aggregation in fish oil-fed rats was also inhibited. Hearts from all rats were subjected to 15 min of global ischemia and 10 min of reperfusion. In hearts of control rats, ischemia-reperfusion resulted in a marked decrease in force of cardiac contraction, increase in coronary perfusion pressure, appearance of ventricular arrhythmias and release of creatine kinase and thromboxane B2 in the coronary effluent. Dietary fish oil supplementation attenuated myocardial dysfunction induced by ischemia-reperfusion, as indicated by smaller change in force of cardiac contraction (-77% vs. -89%, P < 0.05) and coronary perfusion pressure (+37% vs. +71%, P < 0.001). Concomitantly, release of creatine kinase as well as thromboxane B2 in coronary effluent was lower (P < 0.01). Ventricular arrhythmias occurred less frequently in hearts from fish oil-fed rats. Thus, short-term dietary fish oil supplementation attenuates myocardial dysfunction caused by ischemia-reperfusion by a direct effect on the heart independent of blood and plasma components.

The effect of domestic and economic stress on suicide rates in Canada and the United States

The study of the variation in societal suicide rates still is guided primarily by Durkheim's (1897) theory. He proposed primarily a social integration/regulation theory of suicide. One useful way of exploring this theory is from a cross-cultural perspective. Rates of birth, divorce, marriage, and unemployment were analyzed in comparison to rates of suicide from 1950 to 1985 in Canada and the United States. Results generally supported Durkheim's theory except for marriage. There was no association between marriage and suicide in Canada, whereas in the United States marriage had a protective effect once other variables were taken into account. Divorce rates were associated positively and birth rates associated negatively with suicide in both countries. Unemployment rates added little predictive power to suicide rates. A historical perspective and caution about overgeneralizing the results are presented.

A microsatellite-based multipoint index map of human chromosome 22

Utilizing the CEPH (Centre d'Etude du Polymorphism Humain) reference panel and genotyping data for 24 simple tandem repeat polymorphism (STRP) markers, we have constructed a 15-locus multipoint genetic framework map of human chromosome 22. The markers form a continuous linkage group of 51 cM in males and 81 cM in females. Likely genetic locations are provided for 9 additional STRP sequences. The map was constructed employing the CRIMAP computational methodology to build the multipoint map via a stepwise algorithm. The quality of the framework map was evaluated using a battery of statistical diagnostics that suggest a typing error frequency of 0.1% for markers within the map.

Human dystroglycan: skeletal muscle cDNA, genomic structure, origin of tissue specific isoforms and chromosomal localization

Dystroglycan is a novel laminin binding component of the dystrophin-glycoprotein complex which provides a linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. Here we report the cDNA and genomic structure of human dystroglycan. The human dystroglycan is encoded by a single gene (DAG1) mapped to chromosome 3 band p21. The coding sequence is organized into two exons, separated by a large intron. The predicted amino acid sequence of human and rabbit dystroglycan are 93% identical with predicted glycosylation sites being conserved. Human dystroglycan is expressed in a variety of fetal and adult tissues. Our data suggest that muscle and non-muscle isoforms of dystroglycan differ by carbohydrate moieties but not protein sequence. Therefore, we hypothesize that variable glycosylation of the conserved protein core might modulate laminin binding. The relationship of dystroglycan to human diseases is discussed.

Quantitative measurement of nonisotopically labeled polymerase chain reaction product

A novel approach for evaluation of polymerase chain reaction product was described. A biotin-labeled DNA (or RNA) probe is hybridized to the digoxigenin-labeled target PCR product. The hybrids are retained on an anti-biotin antibody-coated plate. An anti-digoxigenin Fab conjugated with alkaline phosphatase is used for generating either a fluorescence or a chromagenic substance. Both fluorogenic and chromagenic systems can be used for quantitative measurement of the PCR product/probe hybrids. The method is specific, fast, nonisotopic, sensitive, quantitative, and practical.

Verapamil and aspirin modulate platelet-mediated vasomotion in arterial segments with intact or disrupted endothelium

OBJECTIVES

This study was designed to examine the effects of verapamil and aspirin, which decrease thromboxane A2 and serotonin release, on the modulation of vascular tone by platelets.

BACKGROUND

Aggregating platelets cause constriction of de-endothelialized arterial segments through thromboxane A2 and serotonin release. These cells cause relaxation of arterial segments with intact endothelium through release of the endothelium-derived relaxing factor.

METHODS

Healthy subjects were given either no drug, verapamil or aspirin for > or = 5 days before their platelets were obtained. The effects of platelets obtained from subjects before and after treatment with aspirin or verapamil on the tone of rat aortic rings were determined.

RESULTS

As expected, control platelets (before verapamil or aspirin treatment) induced concentration-dependent relaxation of rat aortic rings with intact endothelium and a concentration-dependent contraction of de-endothelialized rings. Verapamil treatment enhanced (p < 0.02) the platelet-mediated relaxation in rings with intact endothelium and abolished platelet-mediated constriction (p < 0.01) in the de-endothelialized rings. Aspirin treatment also abolished (p < 0.05) platelet-mediated constriction of the de-endothelialized rings. The de-endothelialized rings contracted normally in response to the synthetic thromboxane A2 analogue U46,619, as well as to serotonin, indicating that the vascular smooth muscle response to thromboxane A2 and serotonin was intact.

CONCLUSIONS

This study provides evidence for the modulation of platelet-mediated vasoconstriction of de-endothelialized arterial segments by prior treatment of subjects with verapamil or aspirin. In clinical syndromes characterized by endothelial dysfunction or disruption, treatment with verapamil or aspirin may modify platelet-vessel wall interactions.

Identification of two hyaluronan-binding domains in the hyaluronan receptor RHAMM

We have identified two discrete hyaluronan- (HA) binding domains in the HA receptor RHAMM (Receptor for HA-Mediated Motility) that mediates the locomotion of H-ras transformed fibroblasts. A complete RHAMM cDNA (1.43 kilobases (kb)) was expressed as a fusion protein with pGEX-2T in Escherichia coli HB101 and was shown to bind specifically to both biotin-labeled HA in a transblot assay and to HA-Sepharose. The complete cDNA was truncated with restriction endonucleases from the 3' end resulting in 1.30-, 1.02-, 0.71-, and 0.41-kb cDNAs which were then expressed in HB101. Only the fusion peptide expressed from the complete cDNA and the 1.30-kb cDNA bound to HA indicating that the region located between 1.02-1.30 kb of RHAMM cDNA was critical for recognition of this glycosaminoglycan. Deletion of 114 bases in this region virtually eliminated HA binding activity thus defining the major glycosaminoglycan binding region to amino acids 400-434 located near the carboxyl terminus of RHAMM. Two domains containing clusters of basic amino acids were identified within this region. Synthetic peptides mimicking these two domains both inhibited HA binding to the complete 1.43-kb expressed glutathione s-transferase-RHAMM fusion protein, and also directly bound to HA-Sepharose. Random peptides and peptides mimicking other regions in RHAMM did not inhibit HA-RHAMM interactions and bound weakly to HA-Sepharose. Oligonucleotides encoding either of these two peptides were linked to the NH2-terminal 0.71 kb of RHAMM which encoded a peptide that did not contain HA binding activity. Fusion proteins containing either of these recombinant peptides acquired HA binding activity as assessed with a transblot assay. Thus, we have identified two domains within RHAMM that are responsible for its HA binding activity.

Role of oligosaccharides in the processing and function of human transferrin receptors. Effect of the loss of the three N-glycosyl oligosaccharides individually or together

When the coding sequence for human transferrin receptors was expressed in a Chinese hamster ovary cell line lacking endogenous transferrin receptors, 86-kDa molecules containing three N-glycosidically linked oligosaccharides were synthesized. These rapidly dimerized to form 172-kDa molecules which increased in size to 190 kDa. After site-directed mutagenesis of all three N-glycosylation sites, 80-kDa receptors were synthesized and only a few dimers were formed. 84-kDa monomers were synthesized in the absence of the oligosaccharide attached to Asn727 or Asn317. Dimerization and maturation through the Golgi body of the Asn727 mutant receptors were much slower than the wild type whereas the Asn317 mutant receptors behaved more similarly to the wild type. Lack of the oligosaccharide at Asn251 gave rise to 73-kDa monomers because of proteolytic processing (Hoe, M. H., and Hunt, R. C. (1992) J. Biol. Chem. 267, 4916-4923), but a second mutation at a potential cleavage site allowed the formation of 84-kDa receptors. These also dimerized at a similar rate to wild type receptors. The three-site mutant receptors were degraded in the endoplasmic reticulum but all three 84-kDa single site mutant receptor species migrated to the cell surface. However, receptors lacking the oligosaccharide at Asn727 bound and internalized little transferrin as a result of reduced affinity.

Identification of hyaluronan binding proteins using a biotinylated hyaluronan probe

A method for detecting hyaluronan (HA)-binding proteins in transblot assays using biotinylated HA (BHA) is described. Some of the binding characteristics of a novel HA receptor termed RHAMM (Receptor for HA-Mediated Motility) are characterized using this assay. The method is also used to detect other HA-binding proteins in tissue homogenates. This method is semiquantitative, rapid, reproducible, sensitive and therefore of potential use in identifying the levels of HA-binding proteins in different cells and tissues.

Quantitative polymerase chain reaction by monitoring enzymatic activity of DNA polymerase

Nucleic acid amplification by polymerase chain reaction (PCR) is a very powerful technique in terms of sensitivity but is limited in terms of ability to perform accurate quantitation. While there is a theoretical correlation between copies of input target sequence and those of PCR product, the quantitative nature of this relationship is obscured by unpredictable variations in reaction conditions and by inhibitory and/or stimulatory substances which might be present in sample preparations, especially those derived from biological fluids. To reliably estimate copies of input DNA target from PCR product, we designed a combination of internal and external control systems coupled to DNA/RNA hybridization and enzymatic immunodetection techniques. The internal control system served to monitor amplification efficiency and to correct for the effects of inhibitors or stimuli on the efficiency of the DNA amplification. The assay is quantitative, nonisotopic, and can be widely applied to assessment of the quantity of DNA present in a wide range of preparations.

Suicide, homicide and unemployment: a methodological note

In multiple regression analyses, the monthly time-series suicide and homicide rates for the USA from 1957-1986 were associated with unemployment and marriage rates. In contrast, annual time-series suicide and homicide rates were not as strongly associated with the social variables.

ExperimentalSalmonella enteritidisphage type 4 infection and egg transmission in Japanese quails

Japanese quails were inoculated orally with 1 x 10(10) colony-forming units of Salmonella enteritidis phage type 4 isolated from chicks to obtain information concerning S. enteritidis infection and egg transmission. The inoculation resulted in a bacteraemic infection with seeding of the liver, spleen, intestine, peritoneum, ovule, ovary and oviduct. Some infected birds showed diarrhoea, ruffled feathers, depression, loss of appetite and death. However, most infected birds remained clinically normal with normal egg production. Salmonella enteritidis was isolated from the albumen of 7, yolk of 15, shell of 13, and shell membrane of 15 of 164 eggs. The experiment suggests that S. enteritidis phage type 4 is invasive for Japanese quails and the infected eggs laid by S. enteritidis infected quails are probably the result of transovarian infection.

Menninger's motives for suicide in the notes of completed and attempted suicides

Brevard, Lester, and Yang in 1990, studying Menninger's motives for suicide, reported more evidence for the wish to be killed (i.e., self-blame or self-punishment) in suicide notes for completed suicides than in parasuicide notes for attempted suicide; however, they did not control for age and sex. A comparison of notes written by completed and attempted suicides that controlled for age and sex showed no differences in the presence of content which reflected Menninger's three motives for suicide, including the wish to be killed.

Sociological and economic theories of suicide: a comparison of the U.S.A. and Taiwan

Time-series analyses were carried out to explore the importance of sociological and economic variables in accounting for the suicide rate in the U.S.A. and in Taiwan for 1952-1984. Sociological variables (divorce and female labor force participation) played similar roles in the multiple regressions for both nations while economic variables (GNP per capita/growth and unemployment) played a role only in the U.S.A.

Fertility and suicide rates: a time series analysis in the United States

In a time series study of the USA from 1933 to 1984, fertility rates were associated with the suicide rates of those aged 15-44. The higher the fertility rate the lower the suicide rate for these age groups, for both whites and non-whites, and for both men and women. The results were seen as supporting Durkheim's theory of suicide.

The impact of the economy on suicide and homicide rates in Japan and the United States

A time series study of socioeconomic correlates of suicide and homicide in Japan and the USA from 1953 to 1982 revealed cross-national differences. Divorce rates were positively associated with rates of personal violence in the USA but negatively associated with these rates in Japan. Unemployment and female labor force participation also correlated differently with rates of personal violence in the two nations suggesting that different theories may be necessary to account for the variation in rates of personal violence in different societies.

Social and economic correlates of the elderly suicide rate

A review of research found that the suicide rates of the elderly show similar regional social correlates as the suicide rates of younger groups and that these rates can be explained using similar sociological theories. Time-series studies in the USA indicate that the impact of economic prosperity on the suicide rate of the elderly is beneficial, whereas the impact on the suicide rate of younger adults is detrimental. The issues raised by this research are discussed.

The relationship between war and homicide rates

A time-series study from 1933 to 1986 in the USA showed that the nation's military participation rate was concurrently associated with lower homicide rates among nonwhite but not white individuals.

The relationship between divorce, unemployment and female participation in the labour force and suicide rates in Australia and America

Identical data sets for Australia and the USA from 1946 to 1984 were analysed to explore the association of unemployment rates, female participation in the labour force and divorce with suicide rates. While female participation in the labour force was related to suicide rates in Australia, unemployment was not. For the USA, both female participation in the labour force and unemployment were related to suicide rates.

Tissue concentrations of prostate-specific antigen in prostatic carcinoma and benign prostatic hyperplasia

Prostate-specific antigen (PSA), as measured in peripheral blood, is currently the most widely used marker for the assessment of tumor burden in the longitudinal study of patients with carcinoma of the prostate (PCA). Studies from other laboratories have led to the conclusion that a given volume of PCA causes a much higher level of PSA in the peripheral circulation of patients than a similar volume of prostate without carcinoma. We have evaluated PSA in the resected tissues immunohistochemically and in extracts of PCA and of prostates resected because of benign prostatic hyperplasia (BPH) with an enzyme-linked immunosorbent assay. Immunohistochemical results were less quantitative than but consistent with the results of the ELISA of tissue extracts. Immunohistochemically, there was considerable heterogeneity in the expression of PSA by both PCA and BPH both within and among prostatic tissues from different patients. While the levels of expression of PSA in these tissues overlap broadly, PSA is expressed at a lower level in PCA than in BPH when PSA is expressed as a function of wet weight of tissue (p = 0.0095), wet weight of tissue/% epithelium (p less than 0.0001), protein extracted from the tissue (p = 0.0039), or protein extracted/% epithelium (p less than 0.0001).

[Biological significance of DNA content in parotid carcinoma]

The DNA content was analysed by flow cytometry in 5 samples of normal salivary tissue, 36 cases of benign salivary gland tumors and 50 cases of parotid carcinoma. It was found that the difference in the DNA index (DI) and proliferative index (PI) in age, sex, tumor size and TNM staging were insignificant (P greater than 0.05). The DI and PI of poorly differentiated parotid carcinoma were much higher than those of well differentiated parotid carcinoma (P less than 0.05). The DI and PI were closely related to the presence of lymph node metastasis (P less than 0.001). The DI and PI of patients with facial nerve paralysis and with disease free period shorter than 5 years were remarkably higher than those with normal facial nerve and disease free survival for more than 5 years (P less than 0.01). The above results indicate that DI and PI, showing cell proliferative kinetic characteristics, can provide reliable and objective parameters for assessing the degree of differentiation, degree of malignancy, biological behavior and prognosis of parotid carcinomas.

[Pharmacokinetics of four benzimidazoles administered intragastrically to mice infected with secondary cysts of Echinococcus granulosus]

Mice infected with secondary cysts of Echinococcus granulosus were treated ig with mebendazole (Meb), albendazole (Alb), albendazole sulfoxide (AlbSO) or albendazole sulphone (AlbSP) at equal effective dosage. The blood concentrations-time courses of the four drugs were adequately fitted to a liner one-compartment open model analysed with a modified NONLIN program, and the major pharmaco- kinetic parameters were then calculated (Table 1). When Alb was given ig to the infected mice, 76.2-84.5% of the drug absorbed was metabolized to AlbSO. There fore, the pharmacokinetics of AlbSO in Alb group was determined. After ig administration of Meb to the infected mice, the ratio of the drug contents in cyst wall to corresponding plasma concentrations of Meb was 10.6-26.9%, but much less in cyst fluid. In Alb and AlbSO groups, similar AlbSO contents in cyst wall and cyst fluid with higher ratio to plasma concentrations were observed (Fig 3). The results suggest that E granulosus cysts were more susceptible to Meb than to Alb or AlbSO, and improvement of Meb absorption would be favourable for enhancement of efficacy in the treatment of hydatid disease.

[Plasma PGI2 and TXA2 levels on a model of PDH in leptospirosis]

Guinea pigs were intravenously injected with icterhemorrhagiae serogroup Lai serovar strain 017 leptospirosis to model the pulmonary diffuse hemorrhage (PDH) in leptospirosis. Thirty-eight hours after the injection, the jugular arteries were catheterized to collect blood sample. The plasma was prepared for radioimmunoassay of TXB2 and 6-keto-PGF1a, the stable metabolites of TXA2 and PGI2 respectively. The plasma level of TXB2 in the experimental group, 107.15 +/- 41.65 pg/ml (n = 7), almost doubled that of the control, 54.05 +/- 12.93 pg/ml (n = 7), with significant difference (P less than 0.01); meanwhile, no significant difference was observed of 6-keto-PGF1a, 67.97 +/- 16.89 pg/ml (n = 6) vs. 98.06 +/- 40.63 pg/ml (n = 9) with P greater than 0.1. The fact that TXA2 causes vasoconstriction and increases vessel permeability suggests that TXA2 elevation should play a role in the mechanism of PDH in leptospirosis.

Differences in the leucine aminopeptidase activity in extracts from human prostatic carcinoma and benign prostatic hyperplasia

Extracts of tissue showed that prostatic carcinomas contain less leucine aminopeptidase activity than benign prostatic hyperplasia. This is true when activity is expressed as specific activity (P = 0.0033), specific activity/% epithelium (P = 0.0007), activity/wet weight of tissue (P = 0.0028), or activity/wet weight of tissue/% epithelium (P = 0.0005). Almost all histochemically demonstrable activity is located in the epithelium. Enzymatic activities in extracts and in histochemical preparations showed similar differences between carcinoma and benign prostatic hyperplasia and were related (R = -0.38, P = 0.0400) to Gleason's grades. The transurethrally resected prostate cancers studied contained no well-differentiated tumors and a high proportion of poorly differentiated tumors. Histochemical activity is absent in most prostatic carcinomas and decreased in others. This observation is particularly interesting in view of the growing knowledge of tumor suppressor genes.

Suicidal behavior and Becker's definition of irrationality

A dichotomy of suicidal individuals previously proposed (impulsive versus chronically disturbed) is shown to parallel a dichotomy of irrational behavior described in 1962 by Gary Becker.

[Toxic principles of Oxytropis glabra DC]

Eight alkaloids were isolated from Oxytropis glabra and identified as anagirine, thermopsine, N-methylcytisine, sparteine, baptifoline, adenine, dictamnine and ethyl allophanate respectively by spectral analysis and physicochemical methods. All these alkaloids were isolated from this genus for the first time and ethyl allophanate was found in nature for the first time.

Social correlates of suicide and homicide in the Austro-Hungarian Empire in the 19th century

Evidence was found for the role of social integration in affecting suicide rates both in a time-series analysis and in a regional analysis for the Austro-Hungarian Empire in the nineteenth and early twentieth centuries. The social correlates of the homicide rates were, however, quite different from those of the suicide rates.