[A case-control study of colorectal cancer in Beijing]

A case-control study was conducted among 250 persons suffering from cancer of the colon and rectum (CRC) in the urban area of Beijing from Jan 1, 1988-June 30, 1989 to explore the risk factors for CRC. 500 neighbour residents were matched as control. The chi-square test and conditional logistic Regression analysis show that high consumption of meat, oil, low occupational physical activity and psychological stress were risk factors of CRC. A trend of increased odds ratio (OR) of CRC with high meat intake and a trend of decreased OR with increased occupational physical activity were found. The high consumption of vegetables and the habit of eating uncooked fresh vegetables showed a protective effect on CRC. The results of the study support the CRC etiological hypotheses of "fat-bile acid action" and "deficiency of dietary fibres".

Selective IgM deficiency and abnormal B-cell response in a foal

Selective IgM deficiency was diagnosed in a 3-month-old Standardbred colt that was referred for chronic respiratory tract disease. Immunoglobulin quantification revealed normal IgG and IgA concentrations, but undetectable IgM concentration. Stimulation of blood lymphocytes with the T-cell mitogens concanavalin A and phytohemagglutinin yielded results within the normal range. However, stimulation with the B-cell mitogen lipopolysaccharide produced no response. A B-cell defect similar to that associated with several immunodeficiency disorders in people was suggested as the cause of the IgM deficiency in this colt.

Clinical value of lung scintigraphy with Tc-99m gluconate in distinguishing benign from malignant lung diseases

One hundred patients were studied with three-phase lung scintigraphy with Tc-99m gluconate. The results showed that there were statistically significant differences between benign and malignant lung lesions in the intensity of accumulation, the blood supply index ratio, and the radioactive uptake ratio. However, no difference was observed between the benign lung lesions and the healthy lungs. Analysis of false negatives and false positives revealed that false negatives had something to do with the cell types of the malignancies, in addition to the relatively small size of the lesions; the false positives were mostly caused by acute inflammation, for which obstructive pneumonitis might be responsible in part. It is concluded that Tc-99m gluconate is tumor-avid and can be used as an agent for positive imaging of lung cancer, because quantitative parameters, blood supply index ratio, and radioactive uptake ratio are more objective in distinguishing malignant lung lesions from benign ones, and are of relatively higher sensitivity and specificity. Thus, lung scintigraphy with Tc-99m gluconate provides an efficient supplementary measure for differentiating between malignant and benign lung lesions.

[Bacterial microcolony and its primary applications]

A new rapid and useful microcolony technique was developed by using cellulose-acetate membrane as a supporter. The bacteria were inoculated on the membrane and cultivated for 3-6h. Then the membrane was rendered, fixed and colored. The microcolonies were observed and counted under the microscope. By using this technique the microcolonies of 139 strains of bacteria were observed. 72 strains of Staphylococcus were differentiated by means of observing the characteristics of the microcolonies. The correlation rate between the microcolony method and the routine method was 90.28%. This technique was also first used to determine the bacteria numbers in urine within 6h, and the advantages of it were significant compared with the plate count method.

Mitochondrial DNA mutation and the ageing process: bioenergy and pharmacological intervention

A comprehensive hypothesis concerning the contribution of mitochondrial DNA (mtDNA) mutations to the human ageing process is reviewed and the implications for cellular bioenergy loss and pharmacological therapy are considered. The central idea is that random mutations in the population of mtDNA molecules of each cell occur throughout life, and that this is a major contributor to the gradual loss of cellular bioenergy capacity within tissues and organs, associated with general senescence and diseases of ageing. An elaboration of four major aspects of the general proposition, together with relevant supporting data, is presented. (1) An extensive array of deletions in mtDNA of many tissues of humans and other mammals has been observed to occur in an age-related manner. (2) The preservation and selection of fully functional mtDNA molecules in the female germ line cells is proposed to occur via a human mtDNA cycle, in which selective amplification of a limited number of mtDNA templates occurs during oocyte development. This proposal explains the endowment of normal neonates with a mtDNA complement minimally contaminated by damaged mtDNA molecules. The phenomena of maternal inheritance and rapid fixation of sequence variants of mtDNA in mammals, as well as selection of cells based on mitochondrial function, are taken into account. (3) Tissue bioenergy mosaics result from accumulated mtDNA damage during ageing, representing different rates of cellular bioenergy loss within individual cells of a tissue. The random segregation of mtDNA during cell division will also further contribute to the tissue energy mosaic. Cells unable to meet their particular bioenergy demand will become non-functional, leading to cell death; the bioenergy threshold is different for the various cell types in the tissues of the body. (4) In order to bioenergetically resuscitate cells and tissues suffering from impaired mitochondrial functions as a result of the ageing process, we propose that redox compounds may be used therapeutically in the pharmacological configurations of a by-pass strategy or as a redox sink therapy. The role of these compounds is to maintain at least part of the mitochondrial respiratory chain function (by-pass) as well as to maintain adequate levels of cellular NAD+ (redox sink) for ATP synthesis, predominantly by the cytosolic glycolytic pathway, with some contribution from mitochondrial oxidative phosphorylation.

An apparently allosteric effect involving N2O with the nitrous oxide reductase from Wolinella succinogenes

It was shown that kcat for the benzyl viologen cation (BV+)-N2O oxidoreductase activity of nitrous oxide reductase from Wolinella succinogenes was 2-3 times greater at high N2O concentrations than at low. This effect of N2O on kcat exhibited a titration curve implicating a single secondary binding site for N2O with a Kd of 130-200 microM (Km with respect to N2O is about 2.5 microM). This work represents the first evidence of an apparently allosteric kinetic effect among nitrous oxide reductases. Its possible cause is discussed. BV+ was generated in these kinetic studies by addition of sub-stoichiometric amounts of dithionite. This means of reduction proved to be superior to the photochemical generation of BV+ that had been used previously with the enzyme. Mass spectrometric measurements suggested that the M(r) of the subunit of the enzyme is about 95,500 rather than 88,000.

Calmodulin stimulation of smooth muscle plasmalemmal vesicle Ca2+ uptake: direct or indirect effect?

Current evidence suggests that Ca(2+)-calmodulin-dependent protein kinase(s) may be involved in the regulation of smooth muscle contractility. The plasmalemmal Ca2+ pump plays an important role in smooth muscle contractility, and this pump is stimulated by calmodulin. However, it is not known whether this is due to direct activation, or calmodulin-dependent protein phosphorylation, or both. We tested these hypotheses using a plasma membrane vesicle preparation from porcine antral smooth muscle. Inclusion of calmodulin in the Ca(2+)-uptake assay decreased the free Ca2+ concentration at which Ca2+ uptake is 50% of the maximal rate (1.5 +/- 0.21 to 0.84 +/- 0.06 microM) of the Ca2+ pump for Ca2+, without changing maximal rate of Ca2+ uptake (Vmax) (8.0 +/- 1.1 to 8.4 +/- 0.7 nmol.min-1.mg-1). In contrast, prephosphorylation in the absence of Ca(2+)-calmodulin increased Ca(2+)-uptake rates at both low (pCa 6.0) and high Ca2+ concentration (pCa 5.0), suggesting an increase in Vmax. Further phosphorylation in the presence of Ca(2+)-calmodulin was not associated with any further increases in the Ca(2+)-uptake rates at pCa 6.0. However, inclusion of calmodulin in the Ca(2+)-uptake assays stimulated the rates (pCa 6.0) of both unphosphorylated and prephosphorylated vesicles to a similar extent. These findings suggest that the stimulation of the smooth muscle plasmalemmal Ca2+ pump by calmodulin is predominantly due to a direct effect via a mechanism distinct from that by plasma membrane phosphorylation.

Insulin mediator stimulation of pyruvate dehydrogenase phosphatases

A two stage assay for detecting insulin mediator based upon its stimulation of soluble pyruvate dehydrogenase (PDH) phosphatase to activate soluble pyruvate dehydrogenase complex (PDC) has been developed. This coupled assay determines the activation of PDC by monitoring production of [14C]CO2 from [1-14C]pyruvic acid. In addition to being more sensitive than the rat liver mitoplast assay previously used, it allows for the separation and investigation of the effects of mediator on the PDH phosphatases individually. It has been previously shown that the insulin mediator stimulates the most abundant PDH phosphatase, the divalent cation dependent PDH phosphatase, by decreasing the phosphatase's metal requirement (1). A metal independent PDH phosphatase has been found in bovine heart mitochondria. This phosphatase is not immunoprecipitated by antiphosphatase 2A antibody, it is not inhibited by okadaic acid, and it is not stimulated by spermine. However, it is stimulated (more than threefold) by insulin mediator prepared from isolated rat liver membranes. It is inhibited by Mg-ATP, with half-maximal inhibition at 0.3 mM; however, this inhibition is overcome by the insulin mediator.

Unusual selective immunoglobulin deficiency in an Arabian foal

A 10-month-old Arabian foal was evaluated for a suspected immunoglobulin (Ig) M deficiency. Decreased to nondetectable concentrations of IgM, IgA, and IgG (T), and a normal concentration of IgG, were present. Results of in vitro testing of the blood lymphocyte blastogenesis showed a weak response to the B-cell mitogen, lipopolysaccharide (LPS), but normal responses to T-cell mitogens. Results of postmortem examination showed synovitis of the left tibiotarsal and both scapulohumeral joints. Atrophy and edema of the lymph nodes and lymphocyte depletion in the thymus and spleen were seen. A subacute inflammatory infiltrate was observed in the kidney, synovium, liver, and brain. Etiologic agents were not identified. This case represents a previously unreported form of immunodeficiency disease in the horse.

Mechanism of impaired growth hormone secretion in patients with Cushing's disease

The function of the growth hormone-releasing hormone (GHRH)-growth hormone (GH) axis in Cushing's disease was studied by monitoring (a) the GH responses to GHRH loading and L-dopa loading, (b) the GHRH response to L-dopa loading, and (c) the daytime profiles of plasma GH concentration. GH release following GHRH and L-dopa was blunted in patients as compared to that in age-matched control subjects. However, GHRH release following L-dopa was similar in patients and controls. The plasma GH levels in four patients measured every 20 min by a highly sensitive immunoradiometric assay for GH showed pulsatile GH secretion at low levels during the observation period. These results indicate that GHRH release from the hypothalamus is preserved in patients with Cushing's disease, and support the hypothesis that glucocorticoid inhibits GH secretion by altering the hypothalamic somatostatin tone.

Physical and genetic mapping of the catA region of Pseudomonas aeruginosa

A prime plasmid has been used as the basis for the construction of a physical and genetic map of a 125 kb segment of the Pseudomonas aeruginosa PAO chromosome. Using pMO1811, a prime plasmid selected for the catA region, a series of Tn5 insertions were obtained which identified two new markers gcu (glycine utilization) and oap (organic acids and alcohols permeability) in the 125 kb region and located them in relation to other known markers of this region. A cosmid bank was constructed from the prime plasmid and an ordered array of cosmid clones for this region identified by restriction endonuclease mapping with EcoRI, HindIII and KpnI, as well as complementation mapping and chromosome walking. By Southern hybridization analyses, it was confirmed that the chromosomal insert carried by pMO1811 was flanked by single, tandemly arranged copies of IS21 and the orientation of the insert on this prime was determined. This cosmid bank provides a resource for the further analysis of this region of the P. aeruginosa genome.

[Contrast sensitivity study in the fellow eyes of patients with central serous chorioretinopathy]

In clinical practice, it has been shown that the contrast sensitivity (CS) test is one of the most sensitive visual functional tests. In our experiment, we used a U.S.-made VCTS 60000 CS test plate to test the fellow eyes (20) of 20 cases with unilateral central serous chorioretinopathy (CSC), along with age-matched normal controls. From the control group, we obtained a group of bell-shaped normal CS curves which showed some degree of decrease with age. 40% of the fellow eyes of the patient group showed a slight CS decrease at mid-high spatial frequencies, though other visual functional tests show no abnormality. These fellow eyes may be at risk for CSC. Our experiment, for the first time, showed the possibility of using the CS test as a diagnostic test for subclinical CSC.

[Electrophysiological effects of different dosage of adenosine triphosphate on normal sinoatrial and atrioventricular node]

In order to study the electrophysiological basis of smaller dosage that would terminate PSVT effectively and decrease side effects remarkably, we have observed the electrophysiological effects of ATP in different dosage (5mg, 10mg, 15mg) on the sino-atrial node (SAN) and atrioventricular node (AVN). Cardiac electrophysiological investigations were carried out in 62 patients with history of PSVT by using the method of trans-esophagus ECG and body surface ECG continuously and simultaneously, during the normal sinus rhythm and PSVT. The results showed that when the effect of 10mg ATP on SAN was not clinically significant yet, it did strikingly block the AVN conduction enough to terminate the PSVT with no severe arrhythmias. 37 cases of 62 patients were provoked PSVT during control electrophysiological study, the PSVTs of 33 cases out of these 37 patients (89.7%) were terminated by using 10mg ATP. There was no serious bradyarrhythmias after PSVT termination. We suggest that 10mg ATP is a reliable dose for PSVT termination.

Selective preglomerular constriction to nerve stimulation in rat hydronephrotic kidneys

The purpose of this study was to quantitate the constrictor responses of pre- vs. postglomerular microvessels during brief increases in renal nerve activity by directly observing the intact microcirculation. To validate the use of the rat hydronephrotic kidney model for this purpose, the vascular reactivity of hydronephrotic kidneys, and normal kidneys was assessed to adrenergic and neural stimulation by quantitating whole kidney blood flow velocity changes elicited by intravenous administration of norepinephrine, electrical stimulation of the posterior hypothalamus, and direct renal nerve stimulation. Hydronephrotic and nonhydronephrotic kidneys responded comparably to norepinephrine and posterior hypothalamic stimulation; however, the hydronephrotic kidneys were less responsive than normal kidneys to direct renal nerve stimulation. In the microcirculatory experiments, stimulation of the splanchnic nerve (2-8 Hz) induced a frequency-dependent constriction of interlobular arteries and afferent arterioles. Preglomerular vessel diameters decreased by 42-53% during the 8-Hz stimulation, whereas the efferent arteriolar diameters did not significantly change. Thus, constriction of preglomerular vessels mediates, in large part, the changes in renal hemodynamics evoked by increases in renal sympathetic nerve activity.

Recovery from exercise-induced desaturation in the quadriceps muscles of elite competitive rowers

A simple muscle tissue spectrophotometer is adapted to measure the recovery time (TR) for hemoglobin/myoglobin (Hb/Mb) desaturation in the capillary bed of exercising muscle, termed a deoxygenation meter. The use of the instrument for measuring the extent of deoxygenation is presented, but the use of TR avoids difficulties of quantifying Hb/Mb saturation changes. The TR reflects the balance of oxygen delivery and oxygen demand in the localized muscles of the quadriceps following work near maximum voluntary contraction (MVC) in elite male and female rowers (a total of 22) on two occasions, 1 yr apart. TR ranged from 10 to 80 s and was interpreted as a measure of the time for repayment of oxygen and energy deficits accumulated during intense exercise by tissue respiration under ADP control. The Hb/Mb resaturation times provide a noninvasive localized indication of the degree of O2 delivery stress as evoked by rowing ergometry and may provide directions for localized muscle power output improvement for particular individuals in rowing competitions.

Multiple mitochondrial DNA deletions in an elderly human individual

We have used the polymerase chain reaction (PCR) to study deletions in the mitochondrial DNA (mtDNA) of an elderly human individual. An extended set of PCR primers has been utilised to identify 10 mitochondrial DNA deletions in a 69-year-old female subject with no known mitochondrial disease. The particular deletions visualised as PCR products depended on the primer pairs used, such that the more distantly separated PCR primers enabled visualisation of larger deletions. Some deletions were common to the heart, brain and skeletal muscle, whereas others were apparently specific to individual tissues. DNA sequencing analysis of PCR products showed that short direct repeat sequences (5 to 13 bp) flanked all deletion breakpoints; in most cases one copy of the repeat was deleted. It is proposed that the accumulation of such multiple deletions is a general phenomenon during the ageing process.

The effect of captopril on glucoheptonate uptake in experimental renal artery stenosis

This study attempted to evaluate the role of glucoheptonate (GHA) in captopril renography in an in vivo laboratory investigation in which postcaptopril glucoheptonate uptake was analysed in awake 2KlC hypertensive rats. Clamped kidney uptake in a previous study was greater in the poststenotic kidney than in the normal kidney (P = 0.01) in rats with mild renal artery stenosis. A glucoheptonate renogram protocol was developed for use in rats anaesthetized with sodium pentobarbital. An 123I-hippuran scan was performed to determine the relative renal function, followed by a control 99Tcm-GHA scan. Five minutes after administering captopril, another 99Tcm-GHA scan was performed. Relative renal uptake was determined between 30 and 90 s postinjection. 99Tcm-GHA uptake in the clamped kidney was more than 50% of total uptake in 3/9 of the abnormal rats' control scans. No abnormal rats clamped kidney 99Tcm-GHA uptake was greater than 50% in the postcaptopril scans. Captopril reduced GHA uptake in all nine of the animals with baseline scans. These findings suggest that the laboratory observation of captopril induced paradoxically increased 99Tcm-GHA uptake in renal artery stenosis may not be observed scintirenographically. Moreover, the data support a potential value of glucoheptonate in captopril renography.

[Review of improving the technology of processing Chinese herbal medicines]

In this paper, the present situation of processing technology for Chinese herbal medicines is expounded in all aspects. Careful processing, overall developing and comprehensive utilization are put forward as improving ways, in the hope of providing a scientific basis for carrying forward the traditional processing techniques for Chinese herbal medicines in producing areas and putting the resources to full and rational use.

[Research of the physicochemical properties of hair in endemic arsenism area]

The paper reports the results of research of hair in the endemic arsenism area where water with arsenic content is 0.58 mg/L in Kuitun district, Xinjiang. In the area of endemic arsenism, the content of hair arsenic with arsenism patients is higher than that of subjects without arsenism. Hair arsenic content among residents was also higher than those of control areas. The stretch and relative strength of hair of subjects living in the area of endemic arsenism were lower than those of the areas of control. The ultrastructure of hair surface has obvious pathologic changes by scanning electron microscope examination. By using a hygienic standard (the arsenic content of water being 0.03 mg/L) to improve the drinking water for two years, the content of hair arsenic has reduced, approaching 95% upper confidence limit for normal hair (1.5 micrograms/g). The stretch and relative strength of hair have distinctly increased. The ultrastructure of hair surface has returned to near normal. The results of our investigation show that we should pay attention to the latent harm to residents in the high-arsenic-content area. The authors consider that hair arsenic content, stretch and relative strength of hair are sensitive and objective indexes to monitor the effects of improving water quality in area of endemic arsenism.

Instabilities of metabolic regulations in aging

1) That non-invasive NMR and optical methods can a) quantify the work stress on mitochondria for ATP production, and b) indicate the tissue O2 tension in the capillary bed that is responsible for the rate of radical generation. 2) That free radical damage to mitochondrial function can be quantified by reciprocal plots of inverse slope giving the extrapolated Vm of mitochondria. 3) That a particular genetically deficient individual requiring high dosages of menadione has survived over 9 years. 4) That mitochondrial deficiency leads to an exercise hyperoxia.