An analysis of unmarried population in Tibet

"This article is intended to analyze the unmarried population above 15 years of age in Tibet based on the 10% machine aggregate data from the 1990 census." Aspects considered include the sex and age composition of the unmarried population, and average and median age at first marriage.

The cryopreserved stented pulmonary homograft valve in the tricuspid position

This study was designed to evaluate the early phase events occurring in a stented pulmonary homograft valve implanted in the tricuspid position. A human pulmonary homograft was sterilized in antibiotic solution for 48 hours and cryopreserved in liquid nitrogen (-176 degrees C). Following thawing and trimming, the pulmonary valve was mounted on a Dacron cloth-covered Delrin stent and implanted into the tricuspid position in 3-month-old sheep, for a mean of 95 +/- 5 days. Seven animals were studied. Morphological assessment indicated good structural tissue preservation despite a decrease in viable fibroblasts noted in the distal part of the leaflets. The collagen fibers remained unchanged, and no tissue calcification was found. Viability of the mounted homograft was evaluated using an in vitro tissue culture method, and the viable cells underwent chromosomal analysis to identify whether they originated from the donor or host. Cells with 56 chromosomes, a number intrinsic to sheep cells, were cultured from the donor recipient junctional area. Hemodynamic and angiographic data, which were collected at the time of both implantation and explantation, revealed no functional deterioration of the implanted valve over 3 months. At the time of explantation, six of the seven valves were competent and no cusp retraction or thickening was noted. The seventh valve had deteriorated due to endocarditis. We conclude that stented cryopreserved pulmonary homografts may be useful as bioprostheses in the tricuspid position.

Physical basis for Descartes ring scattering in laser-irradiated microdroplets

Stimulated Raman scattering from laser-irradiated microdroplets is observed from two distinct spatial regions, the droplet rim and a ringlike region encircling the laser beam axis on the droplet shadow face (the Descartes ring). With the use of two pulsed laser beams, a perturbing beam and a delayed stimulated-Raman-scattering pump beam, the physical mechanism for Descartes ring scattering is investigated. Evidence is obtained of a persistent mechanism that continues even after the perturbing laser pulse is turned off. This mechanism is tentatively identified as electrostriction. The possible existence of an additional prompt mechanism that requires overlap between perturbing and pump laser pulses is also discussed.

[Carrier detection of Glanzmann's thrombasthenia by Taq I restriction fragment length polymorphism of GPIIIa gene]

Glanzmann's thrombasthenia (GT) is an autosomal recessive bleeding disorder in which platelets fail to aggregate in second hemostasis due to qualitative and/or quantitative defect in their GPIIb/IIIa complex. In the present study, both phenotypic and genotypic assays were performed by Western blot and Southern blot techniques in 13 members of 3 GT families. 2 GT carriers of 3 probable carriers whose clinical features and GPIIb/IIIa protein were essentially normal were determined by Taq I/5' GPIIIa RFLP. There were no major deletion or insertion in GPIIIa gene in 4 patients with GT. Thus, the genetic defects in these patients is most likely due to a small change or point mutation in the nucleotide sequence of GPIIIa coding region.

[Experimental cytokinetic study of gastric mucosa in stress ulcer]

Stress ulcer was studied from the view point of cytokinetics by applying 3H-TdR double pulse labelling technique. In combination with clinical practice, the effects of three common preventive drugs Sucralfate (SCR), 25% glucose and Danshen compound were investigated. The results indicated that when stress ulcer developed, the Ts and Tc stage of gastric mucosa in the rat was much prolonged (P less than 0.01), an apparent lowering of 3H-TdR labelling index appeared (P less than 0.01), and significant impact of cytokinetic changes of mucosal cell was only seen in the region of the gastric body but not at the antral portion. SCR, 25% glucose and compound Danshen displayed a considerable protective action against ulceration and this could facilitate the recovery of Ts, Tc stage to normal range (P less than 0.01).

Role of ICAM-1 in neutrophil-mediated lung vascular injury after occlusion and reperfusion

We examined the role of intracellular adhesion molecule 1 (ICAM-1 or CD54) in the development of pulmonary edema in rabbits after pulmonary artery occlusion and reperfusion using a monoclonal antibody (MAb) RR1/1 directed against ICAM-1, a ligand for the CD18 leukocyte adhesion glycoprotein complex. A vascular clamp was placed around the left pulmonary artery for 24 h and then released to allow reperfusion for 2 h. Lungs subjected to 24 h of unilateral pulmonary artery occlusion showed increased binding of 125I-labeled RR1/1 and immunocytochemical evidence of ICAM-1 expression in pulmonary vascular endothelial cells compared with the contralateral lung. MAbs RR1/1 (0.5 mg/kg) or IB4 (1.0 mg/kg) (MAb directed against an epitope on the CD18 adhesion glycoprotein) was infused 45-60 min before the start of reperfusion to assess the roles of ICAM-1 and CD18 in the response. After reperfusion, the lungs were removed, suspended from one end of a weighing balance, and perfused with Ringer-albumin (0.5 g/100 ml), and the changes in lung weight were monitored for 60 min. Lung tissue myeloperoxidase (MPO) content (a marker of neutrophil sequestration) was determined after reperfusion. The increases in lung weight gain in the RR1/1- and IB4-treated groups of 960 +/- 100 and 865 +/- 110 mg, respectively, were less (P less than 0.05) than in untreated controls (3,550 +/- 725 mg).(ABSTRACT TRUNCATED AT 250 WORDS)

A new biological membrane for pericardial closure

In an attempt to develop a new and better biological membrane for the pericardium, we evaluated the use of glutaraldehyde treated human amniotic membrane (AM) and compared it to polytetraflouroethylene (PTFE) membrane as a pericardial substitute. Four dogs underwent a right thoracotomy. Two 4 x 3-cm portions of pericardium, 3-4 cm apart, were excised in each animal and both sites replaced with a similar sized patch of 0.8% glutaraldehyde-treated AM and 0.2-mm PTFE membrane respectively. The AM was sutured to the pericardial defect with its smooth surface facing the epicardium. After 18 weeks, the materials were evaluated. The AM patches revealed minimal extrapericardial and no epicardial adhesion. The PTFE patches had moderate to severe epicardial adhesions and severe extrapericardial adhesions. Histopathological examination of AM patches revealed that the integrity of the AM was preserved, however, neovascularization and slight lymphocytic infiltration were observed. In the PTFE patches, there were severe inflammatory infiltration and fibroblast proliferation into both surfaces. AM patches by virtue of their low immunogenicity evoke very minimal host to graft reaction. These AM grafts, however, tear easily unless carefully sutured. Improved methods of treatment may improve suturing strength. We conclude that AM performs satisfactorily and is superior to PTFE as a pericardial substitute.

A 63-kDa protein with androgen-binding activity is not from the androgen receptor

We have found a new protein in the heart of rat and mice that can be selectively and covalently labelled with the synthetic androgen analog mibolerone. Binding is specific as it can be displaced by excess radioinert ligand. The protein is prominently expressed in liver, kidney, and heart, but not in skeletal muscle. It is water soluble and found in the cytosol. Under denaturing conditions it has a molecular weight of 63,000 and appears on two-dimensional gels with an isoelectric point of 6.3. The protein's affinity for androgen is lower than that of the androgen receptor and it is about 100-fold more abundant than the receptor in the heart. Expression of the protein is not induced by androgen. The presence of this protein in testicular feminization (tfm) mice with a genetical defect of the androgen receptor rules out that it is the androgen receptor or a portion thereof. The biological role of this protein is not yet known.

Observations of Descartes ring stimulated Raman scattering in micrometer-sized water droplets

Stimulated Raman scattering (SRS) from micrometer-sized droplets, which results from coupling of spontaneous Raman emission to droplet morphology-dependent resonances (MDR's), exhibits unique characteristics. Spatial patterns consist of bright SRS arcs on the droplet rim. A second source of SRS emission has recently been observed from a ringlike region encircling the droplet axis near the geometric focus (the Descartes ring). Investigation of the time and spectral characteristics of Descartes ring SRS and its suppression by the addition of absorptive dye to the droplet reveals it to be an additional manifestation of droplet MDR's. We conjecture that the Descartes ring results when the MDR light is scattered by refractive-index inhomogeneities produced by the intense pump field within the droplet.

Determination of infundibular innervation and amine receptor content in cyanotic and acyanotic myocardium: relation to clinical events in tetralogy of Fallot

Right ventricular myocardium was assessed for cholinergic and adrenergic innervation, as well as alpha-adrenergic, beta-adrenergic, and muscarinic receptors, in 18 cyanotic patients with tetralogy of Fallot (TOF) and four acyanotic control patients with ventricular septal defect, each of whom underwent a cardiac repair from June through December 1987. Neurons containing acetylcholine (ACH), neuron-specific enolase (NSE), S-100 protein, neuropeptide-Y (NPY), dopamine-beta-hydroxylase (DBH), and calcitonin gene-related polypeptide (CGRP) were detected surrounding arterioles and myocytes in all specimens. NSE and S-100 immunoreactivities were also identified in the cytoplasm of TOF cardiocytes, possibly indicating a neuroendocrine origin of these cells. Cardiocyte size was increased in TOF (p = 0.05). Acetylcholine (cholinergic) (p = 0.04) and CGRP (cholinergic) positive neurons (p = 0.07) were decreased in the TOF as compared to controls. Adrenergic fiber content (p = 0.15) and beta receptors (p = 0.21) were similar in both groups. There was an increase in muscarinic receptors in the controls (p = 0.002), and a marked increase in alpha receptors in TOF (p = 0.019). There were no intragroup differences in the TOF patients according to degree of cyanosis. In conclusion, there were important differences in neuronal and amine receptor content between TOF and control patients. Increased alpha receptors in TOF could account for differences in clinical and hemodynamic events.

[Application of polymerase chain reaction in amplification of human cytomegalovirus B gene code region]

A nucleic acid amplification procedure, the polymerase chain reaction (PCR), has been used to amplify the human cytomegalovirus (HCMV) B gene code region, and its glycoprotein 52 kd antigenic domain. The primers used in the PCR assay were based on a conserved region of the HCMV B gene sequence. By using primer 1 (5'-AAAGAATTCATGGAATCCAGGATCTG-3', upstream nucleotides 157 to 2877), primer 2 (5'-AAAGAATTCATGAACGTGAAGGAATCG-3', upstream nucleotides 1846 to 2877), and primer 4(5'-ATAAAGCTTAATCAGACGTTCTCTTCTTC-3', downstream nucleotides 157 to 2877 and 1846 to 2877), the HCMV B gene code region sequence and its glycoprotein 52 kd antigenic domain sequence were amplified from the recombinant plasmid pBH1 DNA containing the HCMV B gene. Amplification cycles consisted of denaturation at 92 degrees C for 1 min, annealing at 55 degrees C for 1 min, and extension at 72 degrees C for 1.5 min. The cycles were carried out 30 times in three different water baths, respectively. After the last extension, 10 microliter of each reaction mixture was removed and subjected to electrophoresis on 1.2% agarose gel. Ten microgram of PCR products were obtained from 0.2 microgram of template DNA after the 30 times cycles, and were enough for being used in the restriction site analysis and the construction of clones.

Immunocytochemical detection of atrial natriuretic peptide in periarterial myocardiocytes of cardiac ventricles of adult normotensive rat

The cardiac hormone atrial natriuretic peptide (ANP) is known to be produced by the atrial myocardiocytes. In the ventricles, the concentrations of ANP are very low and are often undetectable by immunocytochemistry. Apart from recent reports of ANP in the various Purkinje cell types, the histological distribution of the small amounts of ANP in the ventricular myocardium has not been well established. In this study, the distribution of ANP immunoreactivity in the ventricles of normotensive adult rats was examined with a modified version of an immunostaining procedure. ANP immunoreactivity was present, in addition to typical myocardial cells, in the myocardiocytes surrounding the arteries and arterioles, particularly at their bifurcations. The specificity of the immunostaining was confirmed with pre-absorption controls. Such a distribution indicates that in addition to being an endocrine hormone ANP may have a paracrine function. The periarterial myocardiocytes may be able to sense the pressure and/or volume changes of the surrounded blood vessels and to release ANP, which may in turn affect these blood vessels and thereby regulate coronary perfusion. The physiological and pathological significance of periarterial ANP distribution warrants further investigation.

Physical overdistension converts ventricular cardiomyocytes to acquire endocrine property and regulate ventricular atrial natriuretic peptide production

Atrial natriuretic peptide (ANP) is present in adult atria but at very low concentrations in normal adult mammalian ventricles. In the atria, the production of ANP is regulated by physical distension of the atrial wall. The same phenomenon was investigated in the ventricles of rats and men. Cardiac tissues from human ventricular aneurysm (n = 5), spontaneously hypertensive rats (n = 30), and rats that had overloaded left ventricles induced by surgery (n = 84) were studied with the methods of light microscopic immunocytochemistry, electron microscopic immunogold staining, and RNA-RNA tissue in situ hybridization. It was found that the levels of ANP gene expression, ANP immunoreactivity, and ANP-containing specific granules in the overburdened ventricles were elevated and their degrees of fluctuation were directly proportional to the force of physical distension applied to the ventricular cardiomyocytes. In rats, ANP mRNA and ANP immunoreactivity returned to the control level seven days after the ventricular overload was surgically released. The changes of ANP and its mRNA in the ventricles were related more closely to the changes of intraventricular pressure than to cardiocytic hypertrophy. In addition, ANP immunoreactivity was demonstrated in Purkinje cells and periarteriolar cardiomyocytes in the ventricles of normotensive rats. In conclusion, physical overstretch of the ventricle wall is likely to be the triggering factor affecting ventricular cardiomyocytes to acquire endocrine property, and also to regulate the production of ventricular ANP, thereby contributing to the control of the blood volume and the blood pressure.

l-tetrahydropalmatine increases leucine enkephalin levels in corpus striatum of rats

The effect of chronic l-tetrahydropalmatine (l-THP) administration on the level of leucine enkephalin (Leu-Enk) in rat corpus striatum was studied. After l-THP sc injection once daily for 2 wk, the striatal Leu-Enk level was elevated dose-dependently. However, a single injection of l-THP failed to change the Leu-Enk level. When rats received sc Sch-23390, a selective D1 antagonist, 15 nmol.kg-1 tid for 2 wk, striatal content of Leu-Enk increased from 0.17 +/- SD 0.03 ng.mg-1 tissue in control group to 0.23 +/- SD 0.05 ng.mg-1 tissue in Sch-23390 group (n = 8, P less than 0.05). Sulpiride (Sul), a selective D2 antagonist, 140 mumol.kg-1 sc given bid for 2 wk had no significant effect on the striatal Leu-Enk content. The results suggested that the blockade of D1 receptors by l-THP might be responsible for the increase of the striatal Leu-Enk content in rat.

A case of basophilic leukemia bearing simultaneous translocations t(8;21) and t(9;22)

We report a case of basophilic leukemia with simultaneous translocations of t(8;21) and t(9;22). The patient's clinical and hematologic findings were characteristic only of t(9;22) but not of t(8;21). This unusual cytogenetic phenomenon raises a challenge to the current concepts of primary chromosomal abnormalities in cancer.

Detection of endothelin-like immunoreactivity in epithelium and fibroblasts of the human umbilical cord

We studied tissue sections of freshly obtained full-term and premature human umbilical cords using polyclonal antibody to endothelin and immunocytochemistry. Endothelin immunoreactivity was detected in the cytoplasm of epithelial cells and primitive fibroblasts, but not in the endothelial cells of both full-term and premature umbilical cords. Immunoelectron microscopy using indirect immunogold staining technique localized endothelin immunoreactivity to the cytoplasm of the epithelial cells and fibroblasts but not confined to any particular structures. No endothelin immunoreactivity was detected in the nucleus or on the cell membrane. Pre-absorption tests with synthetic endothelin-1, -2, and -3 independently established that the immunoreactivity represented endothelin-1 and -2, but not -3. The presence of endothelin-1 and -2-like immunoreactive materials in epithelial cells and fibroblasts of human umbilical cord suggests a role of endothelin in parturition.

Novel system for percutaneous cardiopulmonary bypass

Percutaneous cardiopulmonary bypass (PCPB) has recently come to the forefront of medicine as a technique for resuscitating and supporting patients in various clinical situations. Current systems utilize small-diameter cannulas to aspirate blood under high suction into the cardiopulmonary bypass circuit. Aspiration-based systems have several disadvantages including risk of air embolism, blood hemolysis, and cavitation. Additionally, they are suboptimal for use during open-heart surgical procedures. A system with a venous cannula that employs gravity drainage has been evaluated. Once advanced into position over a guide-wire, the stylet is removed, causing the basket near the end of the cannula to expand. Blood flows into the cannula from side holes and the basket region, which prevents the vessel wall or atrium from collapsing around the catheter and impeding venous drainage. Hemodynamic, hematologic, and histologic examinations were performed on eight anesthetized mongrel dogs during 2 h of PCPB. All animals exhibited adequate tissue perfusion and right and left heart decompression. All animals were successfully weaned from PCPB and after 30 min exhibited normal myocardial function. No ischemic changes were observed in the heart, lung, kidney, or liver by light and electron microscopy. We conclude that full PCPB can be satisfactorily achieved by using a novel percutaneous venous cannula and gravity drainage.

Localized endocrine conversion of ventricular cardiocytes in ventricular aneurysm

Atrial natriuretic peptide (ANP) is synthesized and stored in the atria of the heart, but not or at very low concentrations in the ventricles. We investigated the occurrence of ANP and its messenger RNA (mRNA) in human ventricular aneurysm where the cardiocytes were physically over-stretched. The techniques of light and electron microscopic immunocytochemistry, and RNA-RNA tissue in situ hybridization were employed. A large amount of ANP immunoreactivity was found in the cytoplasm of the cardiocytes in and around the aneurysm, but not in fibrous scar tissue or in the normal ventricles. Immunoelectron microscopy localized the immunoreactivity mainly to specific secretory granules in the cytoplasm of the cardiocytes. ANP mRNA was also detected in these cardiocytes. The abundance of both was much higher than that found in the hypertrophic ventricles of other types. The highest concentration of ANP immunoreactivity and of ANP mRNA was found in the cardiocytes located at the border zone. The quantities of both ANP and its mRNA decreased in cardiocytes more distant from the lesion. Our findings suggest that human ventricular cardiocytes in and around aneurysm can convert to produce large amounts of the endocrine peptide ANP. This ventricular endocrine conversion was localized and was probably caused by physical over-stretch of the cardiocytes.

Determination of N-acetylglucosaminyltransferases III, IV and V in normal and hepatoma tissues of rats

N-Acetylglucosaminyltransferase III, IV and V activities were assayed in various rat tissues and hepatomas using the same fluorescence-labeled sugar chain, GlcNAc beta 1-2Man alpha 1-3-(GlcNAc beta 1-2Man alpha 1-6)Man beta 1-4GlcNAc beta 1-4GlcNAc-2-aminopyridine as a substrate. The N-acetylglucosaminyltransferase III activity toward the substrate is the highest in most rat tissues including primary rat hepatoma. A relatively higher activity for GnT-V is found in small intestine, serum and hepatoma as compared to that of GnT-IV. Some kinetic properties of these enzymes in crude extracts were also determined.

[Quantitative evaluation of human balance function and its significance]

A system of computerized balance function evaluation is introduced. 86 normal chinese adults divided into two age groups tested by the system under 6 standing postures, and a series of normal values of 7 balance parameters and 3 curve diagrams were then obtained. No statistical difference could be found in the values of parameters between male and female. A comparison between the old-age group and the middle-aged and young group revealed no significant difference in each parameter at the time of open eyes with the two feet standing side by side. In terms of closed eyes with the two feet standing side by side, one foot standing in front and the other behind, and single foot standing, the parameters between the two age-groups showed significant difference (p less than 0.05-0.01). The advantages of the system and the value of its application in medical practice, sport medicine, aesthetic medicine, judicature and especially in geriatrics are discussed.

Homograft valve durability: host or donor influence?

Antibiotic sterilized valves have been shown to function longer than those chemically sterilized; however, the reason remains obscure. Current hypotheses cite either retention of donor fibroblasts capable of repairing the grafted valve, or host fibroblast ingrowth into and onto the leaflet ground substance. A cryopreserved aortic homograft from a male donor was explanted from a female recipient after 10 months, and subjected to immunocytochemistry, tissue culture, and karyotyping. The leaflet bases exhibited normal morphology with an intact endothelium. The distal one-third of the leaflets was devoid of fibroblasts from the leaflet bases showed them to be of host origin. This homograft seems to have been implanted with an intact ground substance which allowed for host cell repopulation of the inner one-third of the leaflets. Perhaps donor cell viability in itself is not as important to durability as is preservation of the leaflet ground substance, but rather the presence of viable cells may be an index of the structural integrity of the collagen and elastic matrix.

Pulmonary artery balloon counterpulsation for right ventricular failure after right ventriculotomy in the swine

To assess the efficacy of intrapulmonary balloon counterpulsation in the management of right ventricular failure after right ventriculotomy, we undertook an experimental study in a swine model. To mimic the clinical settings more closely, (1) we left the automatic control of the heart intact (2) did not use cardiopulmonary bypass to support the left side of the heart, and (3) induced right ventricular failure by means of a generous surgical incision (50% to 70% of the anterior wall) of the right ventricle. The criteria set for right ventricular failure were (1) 50% increase in right ventricular end-diastolic pressure, (2) 30% decrease in mean arterial pressure, and (3) 30% decrease in cardiac output. Right ventricular failure was attained in all animals studied: A 230% increase in right ventricular end-diastolic pressure, a 43% decrease in cardiac output, and a 34% decrease in mean arterial pressure were evident after the right ventriculotomy. A specially designed intrapulmonary balloon catheter (Datascope Corp., Oakland, N.J.) was placed into the left pulmonary artery through the right ventricular outflow tract. A Datascope console was used for counterpulsation. Effects of counterpulsation for 40 minutes in a 1:1 mode were assessed after surgical induction of right ventricular failure in 14 swine. Each animal served as its own control. The mean hemodynamic changes are outlined: Right ventricular end-diastolic pressure decreased by 48.9% (p = 0.01). Mean arterial pressure increased by 68.8% (p = 0.01) and cardiac output by 44.2% (p = 0.01). Histologic studies disclosed no morphologic damage to the pulmonary artery or valve in the specimens analyzed. In addition, these results were compared with those in a second group of seven swine in which right ventricular failure was induced by right ventriculotomy and a balloon was placed into the left pulmonary artery but not activated. These results of short-term counterpulsation should be evaluated in a longer term model so as to mimic more closely the clinical setting. If the hemodynamic benefits are duplicated, intrapulmonary balloon counterpulsation should be considered as a simple, effective device when right ventricular failure develops after right ventriculotomy. It effectively improves right ventricular function without damaging the pulmonary artery or valve.

Atrial natriuretic peptide and its messenger ribonucleic acid in overloaded and overload-released ventricles of rat

To study the occurrence of atrial natriuretic peptide (ANP) in overloaded ventricles, suprarenal aortic coarctation was performed on adult rats (n = 60) to induce overloaded left ventricle. In 36 rats, the overloads were released in 2 weeks. The hearts (6 rats in each group) were examined 2, 7, and 14 days after overload and 2, 7, 19, 47, and 77 days after overload release. Another group of 6 rats was coarctated for the second time for 1-6 days after 14 days of coarctation and 7 days of release. ANP immunoreactivity was examined by light and electron microscopic immunocytochemistry. ANP mRNA was studied by RNA-RNA tissue in situ hybridization. ANP immunoreactivity and ANP mRNA were found in the left ventricle 2 days after coarctation, and their amounts increased in proportion to the intraventricular pressure and the duration of coarctation. Two days after release, ANP and its mRNA began to decrease, but at 77 days ANP-containing granules still existed in the ventricular myocytes, whereas its mRNA became undetectable. The second coarctation triggered the release of the remaining ventricular ANP from the first overload and induced another cycle of increased ANP synthesis. Specific granules that do not contain ANP were found in overload-released ventricles, indicating the possible existence of other peptide hormones. These findings suggest that the extents of ventricular ANP gene expression and ANP synthesis and release are regulated by intraventricular pressure, and the occurrence of ANP in overloaded ventricles may not be a transient, immediately reversible phenomenon.

Changes in cardiac neuropeptide Y after experimental myocardial infarction in rat

We have investigated the hypothesis that neuropeptide Y (NPY) is released from noradrenergic sympathetic nerves during experimentally induced myocardial infarction. A left thoracotomy was performed, the left main coronary artery ligated, and the animals sacrificed 4 or 48 h later. NPY levels in heart tissue from these rats and sham-operated controls were measured with radioimmunoassay. Levels of NPY in the right atrium were greater than other regions of the rat heart. After ligation of the left coronary artery, the concentration of NPY in the infarcted area of the left ventricle was reduced at 4 and 48 h when compared to a similar area in sham-operated rats. NPY levels in the septum were unchanged. The results suggest that during myocardial infarction, NPY is released from nerves in the infarcted region and may deleteriously affect increased collateral blood flow surrounding the infarcted tissue.

Comparison of detecting sensitivities of different sizes of gold particles with electron-microscopic immunogold staining using atrial natriuretic peptide in rat atria as a model

The detecting sensitivities of different-sized gold particles were compared in the localization of atrial natriuretic peptide (ANP) in rat atria. The secondary antibodies were goat antirabbit labeled with 5, 15, 30, or 40 nm colloidal gold diluted 1:2 to 1:100 in Tris buffer. The relative quantity of alpha-ANP immunoreactivity in specific granules was determined by subtracting the number of gold particles in 1 micron 2 nongranule area from that in 1 micron 2 granule area measured with a computerized image analyzer. The optimal dilution that achieved the maximal contrast between specific and background label was influenced by the particle size. Optimal dilutions were 1:80, 1:30, 1:20, and 1:5 for 5, 15, 30, and 40 nm gold, respectively. At optimal dilutions, the maximal detecting sensitivity (MDS) was in inverse proportion to the gold particle size; however, this relationship is not entirely linear. The ratio among the MDSs of 5, 15, 30, and 40 nm gold particles was approximately 34:9:3:2. A double immunogold staining was performed to localize alpha- and beta-ANPs with 15 and 5 nm gold, respectively. Both antigens were detected in the same granules. If the ratios established from the single staining data were used, the ratio between the alpha- and the beta-ANP antigens in the same granules was approximately 2.8:1. The data obtained in this study provide a useful reference for applications of immunogold electron microscopy in a quantitative manner, particularly for double immunogold labeling.