Tooth mortality and prosthetic treatment patterns in urban and rural Chinese aged 20-80 years

The study describes tooth mortality levels and pattern of prosthetic treatments in a sample of 1744 Chinese aged 20-80 yr who are residents of Beijing area. Complete edentulousness was rarely seen before the age of 60 yr. Beyond this age up to 26% were edentulous, depending on age and sex. The mean number of teeth present ranged from 10.0 to 29.7 depending on age, sex, and area of residence. Below the age of 60 yr very few persons had experienced extensive loss of teeth but thereafter the number of teeth missing was substantially increased. Prosthetic treatments in the form of partial dentures, crowns, and bridges were frequently observed even in the younger age groups. In all age groups the number of teeth exhibiting caries lesions involving the pulp was much higher than the number of teeth exhibiting extensive mobility. Although many people retain a high number of teeth even late in life our findings indicate a substantial need for, in particular, relief of pain services. Concurrently, emphasis must be placed on preventive programs aiming at interfering with ongoing disease.

Novel arrangement of rRNA genes in Mycoplasma gallisepticum: separation of the 16S gene of one set from the 23S and 5S genes

Large restriction fragments from the DNA of Mycoplasma gallisepticum S6 and PG31, which were prepared by digestion with BglI, BssHII, SmaI, or XhoI and which were separated by pulsed-field electrophoresis, were hybridized with probes containing most, or different parts, of an rRNA operon of Mycoplasma capricolum. The results showed that the genomes contained three widely separated rRNA loci. One locus contained genes for all three rRNA species and another contained 23S and probably 5S rRNA genes, whereas the third appeared to have only a 16S rRNA gene.

[Pacemaker syndrome: a report of 6 cases]

Six patients suspected to have "pacemaker syndrome" were studied with hemodynamic and electrophysiologic methods. Symptoms appeared after implantation of ventricular pacemaker (VVI). Mile symptoms such as dizziness and fatigue and severe symptom of heart failure were noted. The results of the study suggested that cardiac output decreases due to loss of atrial contribution to ventricular filling and also as a result of increase of systemic venous pressure. If the patient has V-A conduction, cardiac output will decrease further. Restoration of atrioventricular synchronization is essential in the treatment of the pacemaker syndrome.

[Electrophysiologic study of concealed accessory A-V pathway]

The presence of concealed accessory A-V pathways (CAP) was demonstrated in 14 out of 18 (78%) patients with supraventricular tachycardia (SVT) and narrow QRS complexes. Such a high percentage of CAP mediated AVRT is a quite unique finding. The importance of a standard programmed electrical stimulation protocol in documenting CAP is emphasized. Careful atrial mapping and premature ventricular stimulation during SVT are very helpful for diagnosis and localization of CAP. We considered that a V-A interval of 75 ms or more on intracardiac electrogram or a R-P interval of 85 ms or more on esophageal electrogram is a good criterion for AVRT utilizing an accessory pathway.

Alterations in blood pressure of normotensive and hypertensive rats following intrathecal injections of neuropeptide Y

The effect of the intrathecal administration of neuropeptide Y (NPY) on blood pressure and heart rate of anesthetized normotensive and hypertensive rats was studied. Neuropeptide Y was observed to produce a decrease in the blood pressure of Sprague-Dawley, Wistar Kyoto (WKY), DOCA-salt, and DOCA-sham control rats. The maximum percent decrease in blood pressure of Sprague-Dawley rats was 12.8 and 15.2% in response to 0.1 and 1.0 nmol NPY, respectively. Similar changes in heart rate were observed. The depressor effect of intrathecal NPY was attenuated by prior treatment with yohimbine and propranolol but not prazosin. The depressor effect of intrathecal NPY observed in normotensive and DOCA-salt hypertensive rats was not seen in the spontaneously hypertensive rat (SHR). The studies extend to the spinal cord the list of regions and tissues where NPY can produce physiological effects. It is concluded that the effects of NPY are closely associated with sympathetic preganglionic neurons in the spinal cord that the depressor effect of NPY involves alpha 2 and beta adrenoceptors, and that a loss of the depressor effect of NPY may contribute to the development or maintenance of hypertension in the SHR.

Characterization of a potential source of barley yellow dwarf virus resistance for wheat

Resistance to barley yellow dwarf virus (BYDV) has been described in lines derived from crosses between wheat and Thinopyrum intermedium. The resistance in one such line, Zhong 4, originating in China, was expressed against two different serotypes of BYDV as measured by accumulation of virus in infected seedlings. F1 hybrids between wheat (2n = 42) and Zhong 4 (2n = 56) had 49 chromosomes and intermediate levels of virus when compared to the parent lines. Cytological and molecular hybridization studies suggested that the BYDV resistance in Zhong 4 is carried on a set of seven pairs of nonwheat chromosomes that derived from a combination of the E and X genomes present in Th. intermedium.Key words: Barley yellow dwarf virus, wheat, ribosomal DNA, Agropyron intermedium, Thinopyrum intermedium, virus resistance.

Prejunctional and postjunctional effects of neuropeptide Y at the noradrenergic neuroeffector junction of the perfused mesenteric arterial bed of the rat

The effect of neuropeptide Y (NPY) on periarterial nerve stimulation-induced release of norepinephrine (NE) and increase in perfusion pressure in the perfused mesenteric arterial bed of the rat was examined. Perfusate effluents were continuously collected and assayed for endogenous NE by high-pressure liquid chromatography (HPLC) coupled to electrochemical detection. Perfusion pressure was continuously monitored by means of a pressure transducer. Periarterial nerve stimulation (8 or 16 Hz, 60 V, 2-ms duration for 30 s) resulted in a readily detectable increase in NE release and perfusion pressure that was attenuated by the prior administration of tetrodotoxin (TTX) (10(-5) M) or guanethidine (5 X 10(-5) M). NPY exerted both prejunctional and postjunctional effects on noradrenergic neurotransmission in this preparation. The peptide produced a concentration-dependent reduction in the release of NE over a concentration range of 10(-10) - 10(-7) M. A similar inhibition effect occurred at 8, 10, and 16 Hz. In contrast, low concentrations (10(-10) and 10(-9) M) decreased the effect of nerve stimulation on perfusion pressure, whereas higher concentrations (10(-7) M) produced a marked potentiation. The alpha 2-adrenoceptor antagonist, yohimbine, did not alter the inhibitory effect of NPY on evoked NE release or the effect on perfusion pressure. Prazosin similarly did not alter the inhibitory effect of NPY on NE release but prevented the increase in perfusion pressure. We conclude that NPY modulates noradrenergic neurotransmission in the mesenteric arterial bed by decreasing the evoked release of NE and producing a concentration-dependent biphasic response on vascular smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Magic and myth of migration: a case study of a special economic zone in China

The town of Shenzhen, China, experienced rapid economic and demographic growth following the government's creation of four Special Economic Zones in 1980. The role of migration in the Shenzhen phenomenon is examined as a practicum for policymakers and demographic specialists. Specifically, the paper is concerned with "the sources and mechanisms of migration, and characteristics of migrants to Shenzhen in order to clarify the relationship between rapid economic growth and its demographic consequences in China. It also briefly assesses the problems associated with migration to Shenzhen and how they may affect the city's future."

Protective effects of captopril and enalapril on myocardial ischemia and reperfusion damage of rat

The protective effect of angiotensin-converting enzyme inhibitors (ACEI) on myocardial ischemia and reperfusion damage was estimated in rat hearts, both in vivo and in vitro. Enalapril 2.5 mg/kg ip pretreatment at 24 and 5 h before coronary occlusion, significantly blunted the rise of CPK (445 +/- 151 vs 649 +/- 244 mu/ml, P less than 0.05) and improved electrocardiogram (ECG) 8 h after coronary occlusion. In global ischemia and reperfusion ex vivo, enalapril improved contractility (0.9 +/- 0.2 vs 0.3 +/- 0.3 g, P less than 0.05) and coronary flow (15.6 +/- 3.3 vs 11.9 +/- 3.1 ml/min/g, P less than 0.05), shortened significantly the duration of reperfusion arrhythmia (3.1 +/- 2.7 vs 9.7 +/- 8.1 min, P less than 0.05). In Langendorffs heart, captopril remarkably preserved force of contraction (2.1 +/- 0.4 vs 1.4 +/- 0.4 g, P less than 0.01) and coronary flow (2.7 +/- 0.5 vs 3.6 +/- 0.9 ml/min/g, P less than 0.05) in segmental infarction deteriorated by angiotensin I. Captopril 10(-5) M infusion reduced the release of CPK (435 +/- 112 vs 640 +/- 123 mu/min coronary flow, P less than 0.05). This action was almost completely abolished by pretreating and infusing with indomethacin. As a positive control, prostacyclin 5 X 10(-7) M infusion further reduced the release of CPK to 330 +/- 77 mu/min. It is concluded that angiotensin-converting enzyme inhibitor can protect both myocardial ischemia and reperfusion damage in rat hearts. The mechanism of protection was ascribed to reduced production of angiotensin II by ACE inhibition and increased prostacyclin release in the myocardium.

[Promoting effect of the Chinese medicinal herb, wikstroemia chamaedaphne and tung oil extracts on carcinoma of the uterine cervix induced by HSV-2 or methylcholanthrene (MCA) in mice]

The promoting effect of the Chinese medicinal herb, Wikstroemia chamaedaphne and Tung oil extracts (WC and HHPA) on carcinoma of uterine cervix induced by HSV-2 or MCA in mice was studied. The results showed that WC and HHPA extracts were not carcinogenic themselves. After carcinogen HSV-2 and MCA treatment, WC and HHPA were added separately. The inducing rates by HSV-2 increased from 7.4% to 21.1% and 26.3%, those by MCA increased from 56.5% to 82.8% and 84.4%. There was a significant difference between the combined groups and groups with HSV-2 or MCA only. The experimental results suggest that these two kinds of extracts play a promoting effect on carcinogenesis. The relation between the carcinogenesis of uterine cervix or nasopharynx and WC or HHPA extracts is discussed.

[The induction of sister chromatid exchange by diethylstilbestrol and mitomycin C in lymphocytes of mothers and their newborn infants]

Lymphocytes of mothers and their newborn infants were treated with varying concentrations of diethylstilbestrol (10(-6) M, 10(-5) M and 10(-4) M) and mitomycin C (0.003, 0.009 and 0.03 microgram/ml), and the incidence of sister chromatid exchanges (SCE) was determined. The results showed that the spontaneous SCE rate in the newborns is less than that of their mothers. A dose-related increase in SCEs was observed in cells exposed to the alkylating chemical mitomycin C, while increases in SCEs were not noted in cultures exposed to diethylstilbestrol. No different susceptibilities of lymphocytes from mothers and newborns to the chemical induction were observed.

DNA hybridization for human papillomavirus (HPV) in cervical lesions. Relationship of the presence of various viral subtypes to expression of HPV structural proteins, involucrin, and carcinoembryonic antigen

We studied cervical tissue from 20 patients with a variety of condylomatous, preneoplastic, and neoplastic lesions to detect various subtypes of human papillomavirus (HPV) at the molecular level by DNA hybridization. In addition, mirror image biopsy specimens were studied by an immunoperoxidase technique for the presence of HPV structural antigens, carcinoembryonic antigen (CEA), and involucrin, as markers of disturbed maturation and/or neoplasia. Of the 20 patients studied, we were able to demonstrate the presence of either HPV 16 or 18, or both, in three of seven squamous carcinomas tested, and three of five dysplasias. Interestingly, two cases of squamous carcinoma and one moderate dysplasia demonstrated HPV types 6 and 11 concurrently with HPV 16 and/or 18. Four of six condylomas showed HPV subtypes 6/11, and only one condyloma showed weak hybridization with HPV 18. Human papillomavirus structural antigen was seen in three of eight condylomas, and three of five dysplasias, but not in any carcinoma. All condylomas showed intense staining for involucrin in full-thickness of the epithelium, but the high-grade dysplasias and carcinomas showed only focal or absence of staining for involucrin. Carcinoembryonic antigen was expressed in 50% of the carcinomas with a pattern similar to that seen with involucrin, but did not correlate with any particular subtype of HPV. The molecular hybridization method seems to be superior for the detection of HPV lesions, and possibly for the prediction of their biologic behavior.

Somatic embryogenesis and plant regeneration in callus from inflorescences of Hordeum vulgare X Triticum aestivum hybrids

Embryogenic callus cultures were obtained by culturing young inflorescence tissues of Hordeum vulgare cv. 'PF51811' (2x)XTriticum aestivum cv. 'Chinese Spring' (6x) hybrids on 2,4-D-containing N6 medium. After subculture for about 10 months the calli retained a high potentiality for somatic embryogenesis and plant regeneration. Of about 300 regenerated plants, approximately 100 were transplanted to potting soil. Eight embryoids and three regenerated plants examined had 28 chromosomes identical to the original hybrid plants, while one regenerated plant was found to be a mixploid composed of cells with 28 and 56 chromosomes. The possibility for obtaining amphiploid hybrids through tissue culture is discussed.

Correlation between lung and plasma angiotensin converting enzyme and the hypotensive effect of captopril in conscious rabbits

We measured both pulmonary and plasma angiotensin converting enzyme (ACE) activity in conscious rabbits before and for 6 days after administration of captopril (2 mg/kg i.v.). Pulmonary ACE activity was measured by means of modified indicator-dilution techniques after bolus injection of [3H]benzoyl-phenyl-alanyl-alanyl-proline ( BPAP , synthetic substrate for ACE). Plasma ACE activity was also determined radiometrically with [3H] BPAP as substrate. In addition, we measured the systemic pressor response to i.v. bolus dose of angiotensin I both before and after captopril. Twenty-four hours after captopril, pulmonary metabolism of BPAP had decreased from control of 73 +/- 5 to 8 +/- 2%; even 6 days after drug treatment there was still evidence of inhibition. In contrast, plasma ACE activity was significantly (P less than .05) reduced within 15 min of treatment (to 20% of control levels) but recovered within 24 hr. The time course of changes in the pressor response to angiotensin I, after captopril, resembled that of plasma ACE activity. Mean systemic arterial blood pressure was 81 +/- 4 torr at control and reached its nadir at 24 hr (64 +/- 2 torr; P less than .05); thereafter a gradual recovery ensued, similar in time course to that of pulmonary ACE. These data suggest that inhibition of plasma ACE and also the pressor response to angiotensin I are unrelated temporally to the hypotensive effects of captopril.

Vascular effects of ginsenosides in vitro

Ginsenosides (saponins extracted from Panax ginseng) elicit qualitatively and quantitatively different responses in isolated, contracted ring preparations of different blood vessels from rabbits, dogs and humans. Ginsenosides themselves did not affect the tone of 'resting' isolated blood vessels directly, but contracted slightly the renal vein of rabbits at the maximum concentration tested. The mixture caused relaxation of the noradrenaline (NA) or prostaglandin F2 alpha (PGF2 alpha)-induced contraction of the pulmonary artery and intrapulmonary artery of rabbits, and the PGF 2 alpha-induced contraction of the canine mesenteric vein. Ginsenosides potentiated, in a concentration-dependent manner, the contractile responses of renal veins of dogs and rabbits to PGF2 alpha The reason for such heterogeneous responses of different blood vessels to ginsenosides in unknown. It is suggested that either potentiation of contraction or relaxation of contracted blood vessels might be mediated by interaction with endogenous vasoactive substances. The potentiation of PGF2 alpha-induced contraction may be related to the reduction of renal blood flow observed in anaesthetized dogs. The simultaneous contraction and relaxation effects may explain its biphasic actions on blood pressure.

Reversible inhibition of poxvirus replication by cycloheximide during the early phase of infection

Infection of primary chick embryo fibroblasts with Vaccinia WR, IHD-W, and cowpox virus even at high m.o.i. does not cause drastic early inhibition of host cell protein synthesis. This contrasts with the infection by these viruses of many eucaryotic cells. Cellular protein synthesis of mouse L cells is also only partially inhibited after infection with cowpox virus up to a m.o.i. of 2500 e.b. As predicted by Moss and Filler (1970, J. Virol. 5, 99-108) no irreversible inhibition of poxvirus replication is observed in these cells following the addition of cycloheximide early after infection. The viral cores which accumulate in chick embryo fibroblasts in the presence of cycloheximide are further uncoated after removal of the protein synthesis inhibitor. These poxvirus host cell systems can be used to identify in vivo immediate and putative delayed early viral gene products. Formation of progeny virus, viral DNA synthesis, the sequential formation of viral proteins, and sensitivity to interferon has been demonstrated in chick embryo fibroblasts after reversal of the cycloheximide block. These studies indicate a synchronized replication cycle of poxvirus after reversal of the cycloheximide block.