Finn T. Black

Hybridization Experiments with Deoxyribonucleic Acid from Ureaplasma urealyticum Serovars I to VIII

Nucleic acid hybridization experiments performed with deoxyribonucleic acid from serovars (serotypes) I to VIII of Ureaplasma urealyticum revealed a clustering of the analyzed strains into two major groups. One cluster included serovars I, III, and VI and the other included serovars II, IV, V, VII, and VIII, the two groups being distinguished at the 40 to 60% homology level. No consistent correlation could be demonstrated between the nucleic acid homology data presented here and the heterologous serological relationships known to exist between different serovars of U. urealyticum. On the other hand, agreement was found between clusterings according to deoxyribonucleic acid homologies and recently published observations made by polyacrylamide gel electrophoresis methods.

Genome Size and Deoxyribonucleic Acid Base Composition of Thermoplasma acidophilum

The deoxyribonucleic acid base composition of two strains of Thermoplasma acidophilum including the type strain 122-1B2 was determined by buoyant density and thermal denaturation temperature. The guanine plus cytosine content of the two strains examined was found by both methods to be about 46%. This result is strikingly at variance with the significantly lower values, about 25%, reported by the group of workers who first described this organism. The genome size, as determined by the renaturation method of Wetmur and Davidson, was found to be about 109 daltons. This is identical with the genome size of members of the family Acholeplasmataceae, order Mycoplasmatales, within which order T. acidophilum has been tentatively classified.

BIOLOGICAL AND PHYSICAL PROPERTIES OF HUMAN T‐MYCOPLASMAS

Although T-mycoplasmas have been known for nearly 20 years, only very little is known about their metabolic a ~ t i v i t i e s , 5 . ~ ~ * ~ ~ * ~ ~ urease a t i v i t y l ~ , ~ ~ being one of the exceptions. A little more is known about other biological properties, such as h e m o l y ~ i s ~ ~ ~ ~ ~ ~ ~ 4 and susceptibility to antimicrobial agents,7~11~21~23~24~27~28 whereas the effect of physical procedures on T-mycoplasmas has been studied in greater detail.1=11*27 The purpose of this study was to test eight serotypes of human T-mycoplasmas by conventional biological and physical methods and, when required, to modify these tests to make them applicable to T-mycoplasmas. The intention was to find out whether the eight serotypes constitute a completely homogeneous group with respect to their biological and physical properties, or if it is possible to differentiate the serotypes.

Genome Size and Base Composition of Deoxyribonucleic Acid from Eight Human T-Mycoplasmas

The base compositions of the deoxyribonucleic acid and the genome sizes of eight serotypes of human T-mycoplasmas are reported. The guanine plus cytosine contents, as measured by thermal denaturation and CsCl gradient centrifugation, are 27 to 28%, the latter method giving slightly lower values. The genome sizes are within the range of 4.1 × 108 to 4.8 × 108 daltons, which corresponds to the values found for members of the family Mycoplasmataceae.

Prevalence of Legionnaires' Disease in Pneumonia Patients Admitted to a Danish Department of Infectious Diseases

During a 14-month study period, 92 patients admitted to the University Clinic for Infectious Diseases with pneumonia were investigated to determine the prevalence and severity of Legionnaires disease (LD). The diagnosis of LD was based on positive serology. Antibodies to 10 different legionella antigens--Legionella pneumophila serogroups 1-6, Fluoribacter (Legionella) bozemanae, F. dumoffii, F. gormanii, and Tatlockia (Legionella) micdadei--were measured by the microagglutination (MA) and indirect fluorescent antibody (IFA) techniques. LD was diagnosed in 22 patients showing a 4-fold or greater rise of MA titers. 10 patients showed a 4-fold or greater rise of IFA titer, 2 had standing high titer. One patient died. Legionella infection was the second most common cause of pneumonia. However, in half of the cases legionella infection occurred concomitantly with Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia psittaci, or viral infections. All 22 LD cases were sporadic. LD had been contracted abroad by 6 patients. Two of the legionella pneumonias were hospital-acquired. Half of the LD patients were older than 60 years. The majority of cases occurred during the winter months. Neither clinical chemistry parameters nor clinical features could distinguish LD from other types of pneumonia.

Saquinavir hard gel suppresses viral load insufficiently in HIV-infected patients naive to anti-retroviral therapy: a retrospective cohort study.

Protease inhibitors are important components in anti-retroviral regimens. In this retrospective study 29 HIV-infected patients treated with a regimen of zidovudine, lamivudine and saquinavir hard gel in 1 centre in Denmark were compared with 58 patients treated with zidovudine, lamivudine and ritonavir or indinavir followed at 5 other centres in Scandinavia. All patients were naive to anti-retroviral therapy prior to institution of the actual anti-retroviral regimen and were followed for a median of 1.3 and 1.4 y respectively. The 2 groups did not differ significantly with respect to age, gender, route of infection, ethnic background, viral load, CD4 count, AIDS at baseline or frequency of clinical controls. Six and 12 months after initiating anti-retroviral therapy, 31% and 34% of the patients on the saquinavir regimen obtained HIV-RNA < or = 500 compared with 76% and 73% in the control group (p < 0.001). In contrast to viral load, the increase in CD4 count did not differ significantly between the 2 groups. In conclusion, we found that with respect to suppression of viral load a regimen of saquinavir, zidovudine and lamivudine seemed to be inferior to a regimen of zidovudine, lamivudine and ritonavir or indinavir.

EVALUATION OF REFERENCE REAGENTS FOR MYCOPLASMAS

The current wide interest shown in mycoplasmology in the fields of human, veterinary, and plant microbiology has created a strong and growing need for the availability of mycoplasma reference reagents, both for practical diagnostic use and for research purposes. For example, the ideal requirement proposed by the Subcommittee on the Taxonomy of Mycoplasmatales,15 that before naming a new species it should be compared serologically with all previously named species of Mycoplasmatales, cannot possibly be complied with by the research worker unless he has access to serum reference reagents. The quality of such reagents should, of course, meet the requirements for adoption as international biological reference reagents. For this purpose a small group of experts participating in an Informal Consultation on the International Programme on Animal Mycoplasma Characterization arranged by WHO and F A 0 in Geneva, Switzerland, in September 1969, discussed basic requirements for establishing mycoplasma reference reagents. A proposal was outlined in a working document and subsequently approved, in 1971, by the FAO/WHO Board on Animal Mycoplasma Characterization. Since this document is not generally available, it may be appropriate to summarize here the requirements agreed upon. The strain chosen for the production of a seed reference reagent for a mycoplasma species should carry all or most of the acknowledged characteristics of the organism and possess satisfactory antigenicity and workability. Normally, these requirements will be met with by the type strain, i.e., the strain designated as the nomenclatural type.8 If not, a strain found to possess these properties, and hence selected as a representative strain, is obviously preferable for the purpose. The strain should be as close as possible to the original isolate in respect to the number of transfers in order to minimize the chance of mutation and the risk of contamination with other mycoplasmas. Before being processed for large-scale production, the purity of the strain should be ensured by means of adequate cloning procedures.15 After cloning, the identity of the seed with the original strain and whether or not it belongs to the species concerned must be checked by biochemical and serological tests. In order to fulfill the requirement of stability both with respect to antigenic and other biologic properties and as regards viability, the seed reagent should be preserved in the lyophilized state. To ensure survival over a long period of storage and to facilitate subcultivation even under suboptimal conditions in less experienced receiving laboratories, the seed reagent should keep a reasonably high titer of colony-forming units (c.f.u.), preferably at least lo5 per ml. Before being released for distribution it should further be ascertained, within limits of present-day knowledge of technology, that the reagent is free of contaminants, including other mycoplasmas in particular. A reference antiserum could be either a Grade I or Grade I1 serum. A Grade I serum, as defined in a working document by the Western and Eastern Hemisphere Committee on Animal Virus Characterization, is a serum that would meet the stringent requirements necessary for adoption as an international biological ref-

The effect of nevirapine in combination with nelfinavir in heavily pretreated HIV-1-infected patients: a prospective, open-label, controlled, randomized study.

Summary: The purpose of the current study was to determine the efficacy and safety of nevirapine combined with nelfinavir and two nucleoside reverse transcriptase inhibitors (NRTIs) in patients previously exposed to highly active antiretroviral therapy (HAART). In a prospective, open‐label, randomized study, 56 HIV‐infected adults who had received HAART, including saquinavir hard gel capsule, ritonavir, or indinavir, were randomly assigned to receive nevirapine in addition to nelfinavir and two NRTIs. The proportion of patients who achieved an undetectable viral load (plasma HIV‐RNA <200 copies/ml) at weeks 24 and 36 was significantly higher in the nevirapine group than in the control group (55% and 52% vs. 22% and 22%; p = .015 and p = .047). No differences in CD4 cell count or clinical outcome were observed. In the nevirapine group, 17% of patients discontinued treatment because of rashes. We conclude that the addition of nevirapine, when switching from one protease inhibitorcontaining regimen to one containing nelfinavir, has a substantial effect on viral suppression.

Normal immunological status in four patients with ectrodactyly-ectodermal dysplasia-clefting syndrome (EEC-syndrome)

Lobster‐claw deformity of the extremities, clefting of the primary and secondary palate, ectodermal dysplasia, and atresia of the lacrimal system are common features of the ectrodactyly‐ectodermal dysplasia‐clefting syndrome (EEC‐syndrome). The patients often suffer from repeated infections of eyes, upper respiratory tract and urogenital system. To exclude an immunodeficiency as cause of the infectious predisposition in patients with EEC‐syndrome, we screened the immunosystem in four related patients with EEC‐syndrome. All patients were found to present normal immunoglobulin production, complement activity, lymphocyte‐, and granulocyte function. We conclude that recurrent infections observed in the EEC‐syndrome are not caused by an immunological defect, but seem to result solely from anatomical anomalies.

EXPERIMENTAL INFECTION OF THE UPPER GENITAL TRACT OF FEMALE GRIVET MONKEYS WITH MYCOPLASMA FERMENTANS

Mycoplasma fermentans inoculated directly into the uterine tubes of female grivet monkeys produced a self-limiting acute salpingitis and parametritis. The inflammation was accompanied by a significant rise in titre of specific indirect haemagglutinating antibodies. Inoculation of M. fermentans into the uterine cavity through the cervical canal without dilatation of the cervix produced practically no signs of inflammation and no antibody response. However, when the intrauterine inoculation of mycoplasmas was followed by currettage of the endometrium, in animals whose uterine tubes had been closed by ligatures, pronounced upper genital-tract inflammation developed, together with a significant antibody response.