Association between DNA ploidy and micronucleus frequency in chronic smokers and impact of smoking cessation

Tobacco use may initiate the process of oral carcinogenesis with clinically undetectable changes. Smoking cessation may prevent its progression. The objective of this study was to evaluate the association between DNA ploidy and micronucleus (MN) frequency in chronic smokers. Three groups were evaluated: Smoker Group, Former Smoker Group and Control Group. Exfoliative cytology was performed on the lateral border of the tongue and mouth floor. MN and DNA ploidy analyses were performed, as well as the correlation between the variables. The data showed a difference between the groups for the total MN (p = 0.0227), and the Smoker group had the highest mean (4.22 ± 4.12). The three groups did not differ statistically from each other on ploidy evaluation (p-value > 0.05). There was also an association between aneuploidy and increased MN frequency in the Former Smoker group (p = 0.0036). In conclusion, these results point out that there is a relationship between the frequency of MN and aneuploidy in former smokers. Moreover, smoking cessation, even for a short period of time, may promote the decrease of MN frequency caused by tobacco use.

Responses of the weed Bidens pilosa L. to exogenous application of the steroidal saponin protodioscin and plant growth regulators 24-epibrassinolide, indol-3-acetic acid and abscisic acid

The exogenous application of plant hormones and their analogues has been exploited to improve crop performance in the field. Protodioscin is a saponin whose steroidal moiety has some similarities to plant steroidal hormones, brassinosteroids. To test the possibility that protodioscin acts as an agonist or antagonist of brassinosteroids or other plant growth regulators, we compared responses of the weed species Bidens pilosa L. to treatment with protodioscin, brassinosteroids, auxins (IAA) and abscisic acid (ABA). Seeds were germinated and grown in agar containing protodioscin, dioscin, brassinolides, IAA and ABA. Root apex respiratory activity was measured with an oxygen electrode. Malondialdehyde (MDA) and antioxidant enzymes activities were assessed. Protodioscin at 48-240 μm inhibited growth of B. pilosa seedlings. The steroidal hormone 24-epibrassinolide (0.1-5 μm) also inhibited growth of primary roots, but brassicasterol was inactive. IAA at higher concentrations (0.5-10.0 μm) strongly inhibited primary root length and fresh weight of stems. ABA inhibited all parameters of seedling growth and also seed germination. Respiratory activity of primary roots (KCN-sensitive and KCN-insensitive) was activated by protodioscin. IAA and ABA reduced KCN-insensitive respiration. The content of MDA in primary roots increased only after protodioscin treatment. All assayed compounds increased APx and POD activity, with 24-epibrassinolide being most active. The activity of CAT was stimulated by protodioscin and 24-epibrassinolide. The results revealed that protodioscin was toxic to B. pilosa through a mechanism not related to plant growth regulator signalling. Protodioscin caused a disturbance in mitochondrial respiratory activity, which could be related to overproduction of ROS and consequent cell membrane damage.

Calcitonin in bone-guided regeneration of mandibles in ovariectomized rats: densitometric, histologic and histomorphometric analysis

The aim of the present study was to investigate bone promotion in surgical defects created in the mandible of normal and ovariectomized female rats using calcitonin associated with a polytetrafluoroethylene barrier. The 100 female rats were divided into four groups: control (C), control treated with calcitonin (CM), ovariectomized control (OV) and ovariectomized treated with calcitonin (OVM). A circumscribed bone defect 4mm in diameter was created in the region of the mandibular angle, and covered with the barrier. Groups CM and OVM received 2 IU/kg of synthetic salmon calcitonin intramuscularly three times a week. The animals were killed 3, 7, 14, 21 and 28 days after surgery. The bone defects were submitted to densitometric, histologic and histomorphometric analysis. Groups C and CM showed higher levels of bone formation after 7 days compared to the OV and OVM groups. A significant difference was observed between groups C and OV at 3-14 days. The OV group presented slower bone regeneration of the surgical bone defect created in the mandibular angle than group C. Synthetic salmon calcitonin accelerated regeneration of the bone defect in the mandibles of OVM animals similarly to group C, and also increased the formation of new bone during the regeneration process in CM.

Hand, foot, and mouth disease: a case report

Hand, foot, and mouth disease is a viral infection related to coxsackieviruses A5, A6, A9, and A10, coxsackieviruses B2 and B5, and echovirus 11. It generally affects children, but this article presents a clinical case of a young woman with hand, foot, and mouth disease. Patients with this disease have oral and skin lesions that may be confused with other diseases. The differential diagnosis is very important because both dental and medical professionals may misdiagnose the disease and sometimes prescribe an inappropriate medication.

Supernumerary mesiodentes with familial character: a clinical report

This article reports the occurrence of mesiodentes in three siblings. The etiology of this condition is discussed and genetic considerations, such as modes of inheritance and prevalence, are discussed.

Electron microscopic detection of human parvovirus (B19) in a patient with HIV infection

We report the findings on an HIV-positive patient found to be infected with human parvovirus B19. In a comparative study of sequential sera, direct electron microscopy (EM) had the same sensitivity as DNA hydridization for the detection of the virus. EM did not require specific reagents and also yielded information on the state of the virus; i.e., whether random or complexed, and the type of antibody involved. The presence of parvovirus complicated the judgement as to drug treatment. This case also highlighted the importance of diagnosing the presence of opportunistic viral infections that have no, or low-grade, pathogenic activity.

Recovery of antigenically reactive HIV-2 cores

Negative staining studies of human immunodeficiency virus (HIV) have been hampered by the fragile nature of the particles. Although detergent treatment is capable of releasing cores from HIV-2 particles, these are unstable and do not retain morphological integrity. Addition of glutaraldehyde will stabilise these structures but, if used at too high a concentration, will destroy their antigenicity. This study shows that if both detergent and glutaraldehyde are used in correct proportions, antigenically reactive cores can be recovered from HIV-2 cell cultures. More specifically we show that a mixture of 0.1% Nonidet P40 and 0.1% glutaraldehyde produces preparations of HIV-2 cores that are suitable for immune electron microscopy. These cores reacted positively, that is, formed immune complexes, with both human HIV-2 antisera and a mouse monoclonal antibody that, although directed against p24 (HIV-1), reacts also with p25 (HIV-2).

Further studies of HIV morphology by negative staining

Thin-section studies of HIV-1- and HIV-2-infected cells were used to establish peak virus productivity and distribution of virus on and around infected cells. Maximum virus yields occurred 7 days after passage; cells at that stage were used as a source of virus for negative staining. Various methods of separating virus and cells were assessed: results showed that gentle homogenization in a Tenbroek-type homogenizer yielded considerably more virus than other techniques. Virus obtained in this way mainly appeared in the form of large clumps. Because of the large numbers of virus particles obtained it was possible to visualize what is probably the immature form of the virus. The inner component of this particle is spherical and, as is discussed, is a transient form proceeding to the now well established, mature, cone-shaped virus core.

The morphology of human immunodeficiency virus (HIV) by negative staining

We have examined preparations of human immunodeficiency virus 1 (HIV-1) and HIV-2 by negative staining electron microscopy. HIV-2 cultures contained large numbers of 130-200 nm particles containing a 130-nm-long by 30-70 nm-wide core. This core is probably of conical or pear-shaped morphology. Some particles exhibited a short fringe that could be seen to comprise a regular arrangement of repeating subunits when visualised end on. Identical particles were found in HIV-1 cultures but in much lower numbers. Attempts to carry out negative staining immune EM were unsuccessful. Also detected in both HIV-1 and HIV-2 cultures were small (70-80 nm) fringed viruslike particles. The possible significance of these particles is discussed.

Rapid diagnosis and management of parainfluenza I virus infection in common marmosets (Callithrix jacchus)

During 1983 a severe episode of respiratory infection occurred in a marmoset colony at these laboratories. Of 91 marmosets, 69 showed clinical signs of disease, one died and nine were so ill that euthanasia was necessary. Eight were examined post mortem and all showed consolidation of the lungs. Laboratory studies were carried out in an attempt to establish the cause of the outbreak and an interstitial pneumonia was found in seven animals which were examined histologically. Direct electron microscopy of nasal swabs and lung samples revealed the presence of a high titre of a paramyxovirus, and subsequent immunofluorescence studies established that the particular paramyxovirus involved was parainfluenza virus type I. Subsequent studies showed that surviving affected animals had seroconverted to parainfluenza I virus while animals that had not been implicated in the outbreak had not.

A regular subunit pattern seen on non-infectious Newcastle disease virus particles

A pseudo-crystalline array of subunits has been observed on particles of the La Sota, in contrast to the Ulster , strain of Newcastle disease virus (NDV) grown in MDBK tissue culture without trypsin. This regular arrangement of subunits was associated with the semi-permissive nature of the tissue culture system, as it disappeared when trypsin, which allows infectious virus to be made, was added. The phenomenon described was considered to be related to the crystalline array of matrix protein which has been described inside the envelope of Sendai virus and NDV by others.

An electron microscope study of three-component immune complexes

Immune electron microscopy has been used to examine the appearance of three-component complexes. The three components are antigen, supplied by two dissimilar viruses, antibody, and a secondary immune reactant. Secondary reagents used in the study are antispecies immunoglobulin (anti-IgG), rheumatoid factor (RF), and complement. Each of these secondary reagents produced cross-linking between antigenically unrelated immune complexes, and it was found possible to distinguish visually the mixed complexes produced by each of them. The significance of the appearance of these mixed complexes is discussed and related to the neutralisation enhancement that can occur in the presence of secondary immune reactants. The appearance of the complexes is also related to the false positive results that can be obtained in carrying out solid phase immunoassays.

Monoclonal antibodies to herpes simplex virus type 1 glycoproteins show that epitope location influences virus neutralization

Three monoclonal antibodies, G8D1 , C2D2 , and TI57 , reacting with herpes simplex virus type 1 glycoproteins have been characterised according to the location of their epitope and ability to neutralize infective virus. Immune electron microscopy and a blocking radioimmunoassay were used to locate the epitopes. The results indicate that the epitope recognised by G8D1 is located on the surface of the glycoprotein fringe, whereas those recognized by C2D2 and TI57 are interior with respect to this. Only G8D1 has neutralizing activity alone, whereas C2D2 can neutralize when antiglobulin is added. Thus, epitope location and density determine the neutralizing capacity of individual antibody molecules.

The use of markers in immune electron microscopy

Immune electron microscopy (IEM) cannot be used successfully for structures that do not have recognisable morphology. However, at least some of these structures or components are related antigenically to recognisable antigens or viruses. We have therefore mixed unknown antigens with known markers and looked for the presence of mixed aggregates. The present study examined a low molecular weight subunit of rotavirus and a micellar form of hepatitis B surface antigen. In both cases mixed immune aggregates were found showing that the unknown components had antigens in common with the established virus or antigen.

The role of rheumatoid factor in an electron microscope study of hepatitis B antigens

An immune electron microscopic (IEM) study of the hepatitis B e antigen (HBeAg) system has shown that rheumatoid factor (RE) can be an important complicating factor when examining preparations containing multiple antigenic specificities. For example, in the presence of RF, mixed immune complexes were produced that suggested HBeAg might be antigenically related to either Dane particles or cores. When RF was removed, however, the putative HBeAg--anti-Hbe complexes showed no relationship with any other hepatitis B component. It has been shown that RF can have a positive practical application in IEM by using it to link preformed marker complexes to immune complexes which do not contain morphologically recognizable antigen.

Practical aspects of diagnostic electron microscopy

The electron microscope technique of negative staining was first used to obtain fundamental information about virus morphology, but in recent years it has developed into a practical method for virus diagnosis. The methods employed are both simple and rapid. The following review discusses in detail the steps that must be taken to obtain good electron microscope preparations and illustrates some of the results that can be obtained.

A new phenomenon (SMOG) associated with solid phase immune electron microscopy

Solid phase immune electron microscopy (SPIEM) has been used to study the interaction of virus and antibody both quickly and with economy of reagents. Unexpectedly, the present study shows that when virus-coated grids are floated on drops of specific antibody the virus particles migrate to form complexes. This has been termed specific migration on the grid (SMOG) and it is suggested that it can be used both to assess the properties of an antiserum and to make virus more readily detectable. The mechanism by which SMOG occurs is not understood but various possibilities are discussed.

A solid-phase system (SPACE) for the detection and quantification of rotavirus in faeces

This report describes the development of a solid-phase haemadsorption system using chromic chloride-linked, antibody coated erythrocytes. It is proposed to call this technique solid phase aggregation of coupled erythrocytes (SPACE). The system is suitable for the detection of virus antigens, such as from rotavirus infections, which are present in 'dirty' or 'mixed' preparations such as faeces, urine or exudates. The test uses microtitre U-form plates coated with specific antivirus antibody; faecal suspensions are added and virus or antigen allowed to adsorb. The plates are then washed and adsorbed antigens are detected by the addition of virus-specific IgG-coated erythrocytes. The resultant settling pattern is read in the same manner as a conventional haemagglutination test. The system is compared with electron microscopy and fluorescent antibody techniques.

A simple immunofluorescent technique for the detection of human rotavirus

If trypsin is incorporated in the tissue culture medium it is possible to carry out a sensitive immunofluorescence assay for the presence of human rotavirus. The enhanced effect of trypsin is negated by serum. It has also been established that naturally occurring enzymes in faeces enable some virus to penetrate tissue culture cells. The role of these naturally occurring enzymes in the pathogenesis of rotavirus infection is discussed.

The effect of sodium thiocyanate on virus structure

A study of two different virus types after elution from immunosorbent columns by sodium thiocyanate has shown that virus degradation occurs. The two virus types studied were hepatitis B and rotavirus. Hepatitis B antigen (HBAg) was only slowly degraded and retained many of its morphological features, although in an altered form; rotavirus was highly sensitive to the chaotropic agent, losing both its viability and its morphological integrity. During the process of disassembly a previously undetected inner component of rotavirus could be visualised, which was termed the "core."

Circulating complexes in leprosy studied by the platelet aggregation test. The platelet aggregation test and its relation to the Rubino test and other sero-immunological parameters in 135 patients with leprosy

Sera from 135 patients with leprosy were tested by the platelet aggregation test (PAT), by the Rubino test and by other sero-immunological assays. PAT positivity (titre≥10) was 53% in the lepromatous subgroups and 5% in the tuberculoid subgroups (P<0·005). The higher PAT titres and Rubino titres clustered significantly (P<0·0005) toward the lepromatous end of the disease spectrum. A statistically significant correlation was found between the PAT and the Rubino titres (0·05>P>0·025). Removal of the effect of the disease spectrum, however, resulted in a partial correlation between the PAT and the Rubino titres that was not significant (P>0·1), suggesting different basic mechanisms for the platelet aggregation (PA) and the Rubino activity of the lepromatous sera. The correlation between the PAT titres and twenty-nine other sero-immunological parameters was calculated, and a highly significant correlation was found between the PAT and the IgG level (P<0·005) and between the PAT and the antistaphylolysin-α titre (P<0·005).

The PA activity in most lepromatous sera studied sedimented in the heavy (>19S) fractions and was inhibitable by IgM rheumatoid factor. It thus fulfilled the criteria for IgG complexes as defined in previous studies with known model Ag/Ab complexes and with sera from patients with immune complex states. The addition of an excess of soluble mycobacterial antigens affected the PA activity of some lepromatous sera, which suggests that the putative complexes were composed of mycobacterial antigens complexed with corresponding IgG antibody.

It was concluded that the PAT is a sensitive detector of IgG complexes peculiar to the lepromatous leprosy. In leprosy the discriminatory power of the PAT seems to be superior to that of other immune complex tests recently applied for the analysis of leprosy series.

Damaged membrane fragments and immune complexes in the blood of patients with Behcet's syndrome

Electron microscopic examination of centrifuged pellets of serum from patients with Behcet's syndrome and recurrent oral ulcers revealed the presence of a large number of membrane fragments. Some of these membranes showed numerous 10 nm holes that were identical to lesions produced by the action of complement. An attempt was made to correlate complement levels, antibodies and cellular immunity with the presence of the membrane fragments, without success. However, a significant correlation was found between the membranes and the IgG class of immune complexes. The finding of membrane fragments with complement-induced damage predominantly in the blood of patients with Behcet's syndrome, and the association with soluble immune complexes suggest that the latter may generate C5b-9 complexes which may bind to the surface of cells in result in cell lysis.

The effect of trypsin on the growth of rotavirus

It has been found that 1000-fold more bovine rotavirus is obtained when trypsin is incorporated in the maintenance medium and allowed to remain throughout the growth cycle. This holds true for primary calf kidney (CK) cells and also for several continuous and semi-continuous cell lines. In the presence of trypsin it has been possible to pass the virus serially on continuous cell lines seven times. Concentrations of 1 to 10 microgram/ml of trypsin are found to be effective. Preliminary results suggest that the same technique will be effective for the in vitro propagation of human rotavirus.

Studies on the structure of a coronavirus-avian infectious bronchitis virus

When avian infectious bronchitis virus (IBV) is fixed in formaldehyde, negative stain is able to penetrate the particle and an internal component is visualized. This component is seen as a tongue or flask shaped structure attached at one point to the outer virus membrane. A model yielding transmission patterns similar to the virus has been made. Gradient centrifugation studies on IBV reveal that the RNP is associated with the internal sac.

Hepatitis B antigen-positive obstetric patients

In a period of six years (1971--77) 9400 sera taken at booking from antenatal patients were examined for hepatitis B antigen (HBsAg), and 40 patients were positive. These 40 patients had 45 pregnancies and were treated with special precautions so far as venepuncture and the management of delivery were concerned. No member of the hospital staff dealing with the patients developed hepatitis B. All infants born to these mothers were normal, two infants were HBsAg-positive at 7 months and 2 years, but are clinically well. No obstetric problems attributable to the HBsAg-positive state were encountered.

Human cytomegalovirus: purification of enveloped virions and dense bodies

Enveloped virions and dense bodies of human cytomegalovirus have been purified by centrifugation, using combination negative viscosity: positive density gradients. Light-scattering bands of each component were obtained, and when these were examined by immune electron microscopy minimal cross contamination was observed.

An antigenic subunit present in rotavirus infected faeces

It has been found by immune electron microscopy that rotavirus-infected faeces, calf or human, contain an antigenic subunit associated with the inner of the two virus capsids. This internal component represents the group specific antigen for the rotavirus group and the subunit reacts with both homologous and heterologous antiserum. It can therefore be used in diagnostic tests and in this paper its use as a reagent for immunodiffusion is described.

Antibody-modification of measles "in vitro" infection

While the involvement of measles-like virus with subacute sclerosing panencephalitis (SSPE) has been shown in many laboratories, the possible mechanisms by which a normal measles infection may lead to the chronic condition are unclear. The work reported here demonstrates that the growth and maintenance of Vero cells infected with the MV 30 strain of measles, in the presence of multivalent antibody, results in a redistribution of the viral antigens within the cells and an alteration in the properties of this attenuated virus which persists even after removal of the antiserum from the culture medium. It is suggested that these in vitro findings could be parallel to the situation that occurs in vivo with measles encephalitis in hamsters and human SSPE.

Concurrent smallpox and chickenpox

Three patients showing smallpox- and chickenpox-like lesions simultaneously were investigated virologically. Both infections were confirmed in the laboratory and, in one case, by electron microscopy.

Formation of virosomes from influenza subunits and liposomes

The surface haemagglutinin and neuraminidase projections of influenza virus were removed from the viral envelope, purified, and relocated on the surface of unilamellar liposomes. The resulting structures were examined in the electron microscope and found to resemble the original virus. Units of both the viral haemagglutinin and viral neuraminidase could be discerned. The name virosome is proposed for these new bodies.

Hepatitis B antigen - an incomplete history

Hepatitis B virus still cannot be grown in an in vitro system; therefore, research into hepatitis B antigen (HB Ag) is limited to laboratory methods such as serology, electron microscopy, and biochemistry. These have established the presence of two distinct antigenic components of HB Ag, that associated with the small forms and the outer covering of the Dane particle (HBs Ag), and that of the Dane particle core (HBc Ag). Current findings make it almost certain that the Dane particle represents the hepatitis B virus (HBV), the smaller forms of the antigen representing excess viral lipoprotein. The group of individuals positive for the antigen are considered and the immunopathology of the disease is discussed. Present understanding of the antigen has made it possible to consider the use of HBs Ag as a means of vaccination. However, further information on the immune mechanisms associated with HB Ag are required before this can be accepted as a general means of protection. Finally, looking at currently available techniques, it would appear that passive hemagglutination and radioimmunoassay are both highly specific and sensitive methods of screening for HB Ag.

A morphological study of the internal component of influenza virus

Rapid treatment of influenza virus directly on the microscope grid with non-ionic detergent had allowed better visualization of the internal component. Many micrographs show that this ribonucleoprotein (RNP) is present as a continuous stand of 6 nm diam. arranged in the form of a double coil or helix. In spite of the minimal treatment to which the virus was subjected most helices still showed signs of degradation. The findings that we have obtained lead us to suggest that the RNP component of influenza virus must be very sensitive to both chemical and physical manipulations, any of which could cause it to fracture from one continuous strand into several pieces, although such breakages could possibly occur at specific points along its length.

Hepatitis B core antigen: immunology and electron microscopy

TWO DISTINCT VIRAL ANTIGENS ARE ASSOCIATED WITH THE HEPATITIS B VIRUS: the hepatitis B surface antigen (HB(s)Ag, Australia antigen) and the hepatitis B core antigen (HB(c)Ag). HB(s)Ag, purified from the serum of asymptomatic human HB(s)Ag carriers, and HB(c)Ag, purified from the liver of a chimpanzee acutely infected with hepatitis B virus, were examined by serological and immune electron microscopic methods. Antisera raised against HB(s)Ag reacted with the outer, surface component of the Dane particle and with the 20-nm spherical and tubular particles present in HB(s)Ag-positive serum, but not with the internal component of the Dane particle or with purified HB(c)Ag particles. Antisera raised against purified HB(c)Ag particles reacted with the internal component of the Dane particle and with HB(c)Ag, but not with the surface of the Dane particle or with the 20-nm spherical and tubular particles associated with HB(s)Ag. Purified HB(c)Ag particles, 27 nm in diameter, demonstrated distinct subunits. The infectious form of hepatitis B virus appears to be represented by the 42-nm Dane particle composed of a 27-nm nucleocapsid core component (HB(c)Ag) surrounded by an antigenically and morphologically distinct lipoprotein surface component (HB(s)Ag).