[Pathogenesis of hematogenic tuberculosis]

The article shows the main prerequisites of the pathogenesis of the haematogenic tuberculosis of man. An account is given of the latency between bacteriaemia and clinical manifestation of various forms of organic tuberculosis and they are illustrated in a table.

Complete DNA methylation does not prevent polyoma and simian virus 40 virus early gene expression

The effect of DNA methylation on polyoma virus and simian virus 40 gene expression was investigated. For this purpose, the cytosines of all C-G dinucleotides of the viral DNAs were methylated by the use of rat liver methylase and the completeness of methylation was verified by dinucleotide analysis and restriction endonuclease treatment. The biological activity of unmethylated and fully methylated DNAs was tested by microinjecting them into tissue culture cells. The functions analyzed included early and late viral gene expression, viral DNA replication, oncogenic transformation efficiency, and virus maturation. No difference in any of these biological functions was observed between methylated and unmethylated DNA. Early gene expression of methylated DNA is not the result of demethylation because viral DNA reextracted from the injected cells, under nonpermissive conditions, retained the methylation pattern of the input DNA. In contrast, viral DNA extracted from transformed cells or from intact virus particles was partially or completely demethylated.

[Tuberculin testing in 15 and 16-year-old students, who, as newborns, were vaccinated with BCG]

Tuberculin testings with 2 T.U. (PPD RT 23 + Tween 80) of fifteen- and sixteen-year-old people cause reactions only in 17.4%. BCG-vaccinations of all sixteen-year-old persons are still necessary.

[Pathogenesis of pulmonary tuberculosis from the current viewpoint]

The multiform pathogenesis of tuberculosis in vastly clear now. In the article are quoted the main perceptions, and the possible developments of pulmonary tuberculosis are illustrated by a diagram.

Towards purification of the scrapie agent

A method for the partial purification of scrapie infectivity from hamster brain is described. About a 100-1000-fold, 20-fold, and 200-fold enrichment in scrapie infectivity with respect to protein, RNA, and DNA content has been achieved using differential centrifugation, enzyme and detergent treatment. The inbred CLAC strain of hamsters used in our experiments contained about 10 times less infectivity in brain than has been found in randomly bred animals or other inbred strains.

A case-control study of the association of sickle cell trait and chronic open-angle glaucoma

Chronic open-angle glaucoma is reported to be more common in blacks than in whites. The reasons for a higher prevalence of this disease in blacks are unclear. Two recent small case series from clinical practice have been published in which secondary open-angle glaucoma was diagnosed in blacks with sickle cell trait who had experienced either traumatic or nontraumatic hyphema. The association of sickle cell trait and chronic open-angle glaucoma has been tested only in a small case-control study of uncontrolled chronic open-angle glaucoma patients undergoing surgery. No significant association was found. However, the higher prevalence of sickle cell trait in blacks compared with whites raises the question of whether the presence of sickle hemoglobin is a risk factor for chronic open-angle glaucoma in the black population. To test for a possible association between this disease and sickle cell trait, we conducted a case-control study in black ophthalmic patients at the University of Pennsylvania and affiliated hospitals between December 1981 and July 1982. Sickle cell trait, as measured by the sickle cell preparation test, was no more prevalent in patients with chronic open-angle glaucoma than in age- and sex-matched ophthalmic clinic controls. It is unlikely that hemoglobin SA is a risk factor for chronic open-angle glaucoma.

Retrovirus genomes methylated by mammalian but not bacterial methylase are non-infectious

The biological importance of DNA methylation for gene expression in eukaryotes is becoming increasingly evident, and a direct role of methylation in gene expression has been suggested by an analysis of the infectivity of integrated retroviral genomes in a transfection assay. These studies, however, did not address whether specific methylatable residues are involved in gene regulation. Methylation by sequence-specific bacterial DNA methylases has been shown to suppress the expression of some genes, but not others. To investigate the effect of methylation on gene expression without having to rely on sequence-specific methylases, a rat liver enzyme was used to methylate in vitro all C-G dinucleotides of a proviral genomic clone. This treatment reduced the biological activity of Moloney murine leukaemia virus (M-MuLV) proviral DNA by more than three orders of magnitude, whereas complete methylation of 35 HpaII sites in the same DNA had only a marginal effect. The rat methylase-induced inactivation was reversible, as treatment of recipient cells with 5-azacytidine rendered the non-infectious viral genomes biologically active. This suggests that methylation in other C-G dinucleotides than those detectable with restriction enzymes can be crucial for gene expression.

[Human and mammalian infections caused by Mycobacterium tuberculosis, Mycobacterium bovis and atypical Mycobacteria]

In a short survey the connections between tuberculous diseases of man and those of mammals are described. For the combat against tuberculosis a good knowledge of the interactions involved is necessary. The characteristics of such causative agents as Mycobacterium tuberculosis, Mycobacterium bovis and atypical mycobacteria are made clear.

[Subacute and subchronic percutaneous tolerance testing (28-day and 90-day test) of epicutaneously applied dis-infectants as demonstrated by the example of peroxyethanoic acid (author's transl)]

As compared to control animals, guinea-pigs to the shaved backs of which a dose of 0.16 ml of a 0.12% solution of PES/100g. of body mass had been applied twice daily for periods of 28 and 90 d, respectively (5 d of application being followed by 2 d without treatment), showed erythema, loss of hair, slower increase in mass, increased heart rate, smaller body mass/kidney mass and body mass/spleen mass ratios, increases in leucocytes, ASAT, ALAT, LDH I and LDH III. In the 28-d test, slight inflammatory symptoms of the liver, kidneys and heart were observed in the experimental animals. These symptoms were more marked in the 90-d test, granulomata in the livers being particularly striking. A pneumonia of moderate to very marked degree is suggestive of the activation of a clinically latent PES infect whereby the inflammatory alterations in the kidneys might be explained by the formation of metastases.

The effects of mechanical factors on bio-compatibility tests

Evaluation of materials for bone and joint replacement has led to contradictory results in a number of cases: some researchers have reported the formation of good load-bearing bone structures along the surface of a particular material, e.g. dense, high strength Al2O3-ceramics, others found the same material encapsulated by soft tissue. Considering the results of various animal experiments and the evaluation of clinical follow-up studies, it can be shown that many of these conflicting observations are due to different biomechanical conditions at the site of examination. Failure to consider the local load situation at the interface between the implanted specimen and the bone tissue can lead to misleading statements about the possible applications of a material.

Influence of routine administration of folic acid and iron during pregnancy

Haematological and folic acid status were assessed in 200 women in the 6th month of pregnancy. Folic acid deficiencies with no or little haematological impairment were found in one third of the cases, and their occurrence increased when the socioeconomic level was low. During the last trimester of pregnancy, the women were given either iron alone or iron and folic acid supplementation. In the mothers, the rise of folate values in serum and red blood cells, in the folic acid-supplemented group, had no obvious haematological consequences, showing that iron therapy alone can, in developed countries, prevent the anaemia in pregnancy. In the infants, there was no difference in the haematological indices, whatever the mothers' treatment had been. However, a significant difference appeared for the gestational age and, therefore, the height and weight. Folic acid supplementation during pregnancy increased its duration by virtually 1 week.

Partial parenteral nutrition in preterm and newborn infants during the first three days of life

Eight preterm infants, five with postnatal asphyxia, as well as two hypotrophic neonates and one term infant with severe postnatal asphyxia (mean birth weight 2300 g) were fed, in addition to oral nutrition, partially parenterally with glucose solution and mother's-milk-adapted amino acid solution during their first three days of life. By increasing protein supplies with a parenteral share of more than 50% during the three days, the nitrogen balances were positive on all days, although the calories supplied were far below the postulated optimum. On days 2 and 3, nitrogen retention was about 60% of the supply. Every 4 hrs after discontinuation of the 16 hr amino acid infusion, the amino acid levels in the plasma were examined by column chromatography. The resulting mean values did not show any imbalances of amino acid homeostasis. The maximum mean loss in weight of the present groups was 4% of the birth weight during the first 10 days of life and thus equalled the loss in weight of normal healthy preterms. Clinical and chemical parameters did not reveal any disadvantageous side effects of partial parenteral nutrition.

Application of ferrokinetic investigation for differential diagnosis in bone marrow hypoplasia and their clinical relevance

In this study, erythropoietic activity of bone marrow has been evaluated by ferrokinetics. For that purpose, the data of radioiron disappearance from plasma and its ultimate incorporation in red blood cells after the injection of about 10 muCi of 59Fe tagged autologous plasma, were analysed and fitted to the sum of three exponentials, using a non-linear least square SAAM-25 program on UNIVAC-1108 computer. A function representing time-activity relationship, was constructed. The functional physiological model of iron metabolism, proposed by Cavill and Ricketts, was used to calculate various ferrokinetic parameters in terms of coefficients and exponents of the time-activity function. After identifying the parameters that could be used as indices of erythropoietic activity of bone marrow, the study was repeated in six patients after they had undergone myelostimulative therapy. A distinct correlation was found between ferrokinetic observations and clinical and biochemical findings. It has been demonstrated that in histologically diagnosed cases with bone marrow hypoplasia, a further differentiation between pure aplasia and those with hypoplasia together with ineffective erythropoiesis was possible. This discrimination which is clinically very important, is only possible by means of kinetic investigations.

Direct anchorage of Al2O3-ceramic hip components: three years of clinical experience and results of further animal studies

The biocompatibility of high-purity dense Al2O3-ceramics had been shown to open the possibility of direct cement-free anchorage of joint endoprostheses. Three years of clinical experience with ceramic-metal composite total hip prostheses confirm the biomechanical design criteria used for the acetabular components. They also allow for additional conclusions regarding the reaction of bone tissue towards a bioinert implant. Further research activities are directed towards a solution for biomechanically stable anchorage of the femoral component of hip prostheses.