Mechanism of action of retinyl compounds on wound healing IV: effect of desmethylretinoic acid and its vinylogs on granuloma formation

The effect of side-chain length of desmethylretinoic acid on granuloma formation induced by implantation of cotton pellets was studied. As in the homologous series of retinoic acid studies, compounds with side chains shorter than retinoic acid were not active while compounds with side chains as long or longer than retinoic acid were active. The compound with a chain two carbons longer than retinoic acid was the most active. The hydroxyproline and hexosamine contents of the granuloma were analyzed. The mechanisms of action of these active compounds on wound healing are discussed.

The laboratory diagnosis and epidemiology of Mycoplasma pneumoniae in Switzerland

The analysis of approximately 60,000 serum samples collected from patients with different clinical symptoms between 1965 and 1975 in Switzerland yielded positive reactions indicating a recent infection with Mycoplasma pneumoniae in 2-30% during this period. Among 1,555 patients with clinical symptoms of an acute respiratory infection, 359 patients or 23% had antibody titers indicating a recent infection with M.pneumoniae. On the basis of these results it is concluded that M.pneumoniae is the most frequent cause of acute infections of the respiratory tract.

IF-40. A new polystyrene microscope tray for immunofluorescent studies

A polystyrene plate is described which was designed to replace microscope slides for routine immunofluorescent examinations. The plate has 40 flat indentations of 8 mm diameter. The plates can be sterilized and stored in plastic bags. They are well suited for drop preparations or application of cryostat slices of biopsy and necropsy material, and tissue cultures can be grown directly in the indentations. When compared with glass microscope slides, which have long been used for these purposes, the polystyrene plates offer a variety of advantages. Cells can be grown directly in the indentations without washing or pretreating the trays in any way. The indentations prohibit mixing of samples or reagents and enable the use of smaller quantities of reagents. Up to 40 samples can be worked up simultaneously on one plate, or a plate rack can be used for the processing of up to 400 samples at once. The use of a special stage enables easy microscoping of all 40 spots without further handling of the tray.

Phytohaemagglutinin-induced lymphocyte transformation and histologic findings in patients with chronic aggressive hepatitis before and during immunosuppressive therapy

In vitro lymphocyte transformation (14C-thymidine incorporation rate following stimulation by PHA) was studied in 19 patients with histologically proven chronic aggressive hepatitis. In the majority of the cases measurements were performed prior to and during a combined (azathioprine/corticosteroid) immunosuppressive therapy. In comparison to normal controls, the majority of the patients showed a significantly reduced lymphocyte transformation before the treatment started. During the immunosuppressive therapy there was a normalization of PHA-responsiveness in most of the patients, or an improvement, at least. Bioptic control seems to be the most reliable parameter to prove a therapeutic effect, since the histologic criteria for a decrease of the inflammatory activity were the last to occur. After transient cessation of the therapy, in 4 out of 6 cases a decrease of lymphocytic PHA-responsiveness was developed again, paralleled by histologic activation of the process where biopsy could be performed. This observation favours a long-term therapy for at least several years.

Evidence of chronic persistent infections with polyomaviruses (BK type) in renal transplant recipients

Ten renal transplant recipients showing a significant increase in human polyomavirus antibodies, indicative of an acute infection, were followed up serologically over periods ranging from two months to more than two years. Fifty-four serum specimens were available for the study and they were tested by both haemagglutination-inhibition and complement-fixation. Polyomavirus antigens were prepared from the BK and SV40-like strains of polyomaviruses, and from the SV40 virus. One strain of polyomavirus, related to the BK strain was isolated from the urine of one of these patients. Two other BK strains were recovered from the urine and kidney, respectively, of transplant recipients not included in this study. Sera of these two patients were not obtained until the transplantation was made; they were already highly positive for polyomavirus antibodies, precluding the demonstration of an increase in antibody titer. Serologic results have shown that HAI antibodies persist at high titers throughout the observation period. This persistence ranged from two to four months (four cases), seven to eleven months (three cases) and thirteen to twenty months (three cases). In none of the cases could a decrease of high titer be demonstrated. Moreover, density gradient studies have shown that specific IgM antibodies also tend to persist over many months. Similar serologic results were obtained in complement-fixation tests with a BK antigen. Titers were at least 1 in 30 in the study group, but were not observed among healthy blood donors. All sera were uniformly negative for SV40 and SV40-like antigens. One polyomavirus isolation was successful from urine obtained six months after initial serologic evidence for a polyomavirus infection. The other two viruses were isolated from materials taken four and seven months after first detection of polyomavirus antibodies at high titer. Both serologic evidence and viral isolations seem to indicate that polyomaviruses (BK type) might cause a chronic infection in humans.

Virus infections in renal transplant recipients

534 serum samples from 73 renal transplant recipients, 41 haemodialysis patients, and 99 blood and organ donors were examined serologically for antibodies against Cytomegalo, H. simplex (types 1 and 2), Varicella-zoster, Epstein-Barr, Adeno, Influenza, Parainfluenza, Respiratory syncytial, Measles, Picorna- and human Polyoma- Viruses. Serum specimens were stored in the lyophilized state until examined thus enabling a simultaneous testing of all samples belonging to one patient. All antigens, complement, and control antisera were prepared, lyophilized, and standardized in this laboratory. This has enabled the use of single batches of any preparation throughout the study. Serologic results with antigens of the Herpesvirus group (CMV, HSV and VZV) compared favourably with previous results showing that infections with these agents, especially with CMV, can frequently be encountered among transplant recipients. Our results have indicated a moderately increased incidence of infections with some Herpesviruses in haemodialysis patients as well. Infections with VZV, for instance, were as frequently demonstrated in these patients, as in transplant patients although the former received no immunosuppressive therapy. Serologic results with non-Herpesvirus antigens indicated an increased incidence of infections with Polyomavirus, Myxoviruses (Influenza, Parainfluenza and RS) and Picornaviruses among transplant recipients. The incidence of acute infections with RS virus among adults was unusually high and there is no evidence so far to indicate such a high frequency of RS infections in any other group of adults. We were unable to demonstrate acute infections with non-Herpesviruses among haemodialysis patients, even though most of the patients were followed over a period of more than 2 years. Virus isolation attempts were performed with samples of urines and biopsy or autopsy samples. 23 out of 28 cytopathic agents recovered from urines, throat-swabs and/or from organs of transplant recipients were identified as CMV. Two HSV type 1, 1 HSV type 2, and 2 Coxsackie B type 3 viruses were also isolated. No viruses were isolated from a series of 31 kidneys randomly selected among autopsy cases.

Lyophilization of human cytomegaloviruses

Lyophilization of CMV strains was performed at O°C or at 25°C with or without the addition of Parke, Davis additive. Dried viral preparations were thereafter stored at 4°C or at -20°C and tested for infectivity. The results of experiments have shown that CMV can be lyophilized at O°C with little or no loss of infectivity. In contrast, lophilization at 25°C resulted in a considerable loss of infectivity. The infectivity of lyophilized preparations decreased slowly during storage at 4°C, but infectious virus particles could be still detected 523 days after lyophilization. As a rule, the infectivity of lyophilized CMV could be quantitatively preserved at -20°C for at least 191 to 235 days. The use of an additive did not seem to have significantly protected the CMV during lyophilization, but some evidence has been obtained showing a certain protection of lyophilized preparations during storage at -20°C.