Treatment of infections due to multiresistant Neisseria gonorrhoeae with sulbactam/ampicillin

Between January and April 1984, 229 of 448 male patients with urethritis at the Choong-Ku Venereal Disease Clinic in Seoul had positive urethral cultures: 66 for penicillinase-producing Neisseria gonorrhoeae (PPNG) and 163 for non-penicillinase-producing N. gonorrhoeae (non-PPNG). Forty-five men with PPNG urethritis were enrolled in a study of the efficacy of treatment with sulbactam/ampicillin plus probenecid. Diagnosis and evaluation of cure were based on culture results. The agar-plate dilution method was used for susceptibility testing, and the chromogenic cephalosporin test was used for detection of beta-lactamases. MICs of various antibiotics for the isolates were high. MICs of sulbactam/ampicillin were 0.25-4 micrograms/ml, with an MIC90 of 4 micrograms/ml, a value 16-fold lower than that for ampicillin alone (MIC90 greater than 32 micrograms/ml). Patients were treated with 1 g of probenecid orally and either one vial of sodium sulbactam/ampicillin or two vials intramuscularly. Each vial contained 0.5 g of sodium sulbactam and 1 g of sodium ampicillin. Patients were followed up for three to five days. All patients but one were cured, and no remarkable adverse reactions were noted. The two regimens of sulbactam/ampicillin were equally effective in the treatment of uncomplicated PPNG in men.

Cystic Mural Nodule in Cerebellar Hemangioblastoma

An example of a form of cystic hemangioblastoma of the cerebellum in which the mural nodule itself showed a central cystic area is presented. Although the precise etiology of the cystic component within hemangioblastoma tumor nodules is not known, it probably results from tumor degeneration. Computed tomography is valuable in identifying this feature, which, if present, is very suggestive of the diagnosis of hemangioblastoma. Other diagnostically useful CT features of hemangioblastoma that were present in this case included location of the mural nodule adjacent to the nearest pial surface, isodensity of the nodule on the preinfusion scan, and very rapid circulation of contrast material through the wall of the nodule, demonstrated by dynamic CT technique.

Cartilage involvement in laryngeal carcinoma: correlation of CT and pathologic macrosection studies

Fifteen patients with laryngeal epidermoid carcinoma underwent CT of the larynx prior to surgery. Whole mount sections of the extirpated larynx cut in the horizontal plane were compared with the corresponding level of the preoperative CT sections. This study in particular was designed to evaluate the accuracy of diagnosing cartilage involvement by CT and to correlate CT findings with histologic involvement. Our results indicate that CT correlates well with anatomic location of gross cartilage involvement by the tumor; however, small macroscopic invasion of the laryngeal cartilages may be difficult to diagnose with CT. Microscopic involvement of the cartilages cannot be diagnosed with CT. Decisions regarding conservation surgery cannot be based on CT evaluation alone.

Tumor formation by SV40-transformed human cells in nude mice: the role of SV40 T antigens

Human cells transformed in vitro by SV40 rarely form tumors in nude mice. We examined whether these cells as a group are inherently nontumorigenic or whether they are potentially tumorigenic but rejected by the athymic host, possibly by nonspecific immune mechanisms. SV80 and NG8 are SV40-transformed human cell lines that express all of the transformed properties, including anchorage-independent growth, but do not form tumors in adult nude mice after injection of as many as 10(8) cells. Both the SV80 and NG8 cell lines have SV40-specific transplantation antigens which crossreact with those present on SV40-transformed (but tumorigenic) rodent cells. We found that SV80 cells, though not NG8 cells, induced progressively growing lethal tumors if the cells are injected repeatedly into neonatal nude mice. Somatic cell hybrids between SV80 or NG8 cells and a highly tumorigenic cell line derived from a human tumor continue to express the virus-induced antigens and fail to form tumors in adult nude mice. These results strongly suggest that at least for some SV40-transformed human cells, the failure to form tumors in nude mice may be due to their expression of virus-induced transplantation antigens rather than the absence of tumorigenic potential.

Inhibition of excision-repair of ultraviolet damage in human cells by exposure to methyl methanesulfonate

Unscheduled DNA synthesis and excision of pyrimidine dimers in human cells exposed to ultraviolet let were inhibited by exposure to methyl methanesulfonate (MMS, 1-2 mM), but repair of MMS damage was not inhibited by UV light. Because the pathways for excision of pyrimidine dimers and alkylation damage have previously been shown to be different, this observation implies a direct effect of alkylation on repair enzymes. We estimate that if inhibition is due to protein alkylation, the UV repair system must present an extremely large target to alkylation and may involve a complex of protein subunits in the order of 1 million daltons such that 1 or more alkylations occur per complex at the concentrations used. These results also indicate that the method of exposing cells to 2 DNA-damaging agents to determine whether they are repaired by common or different pathways can be quite unreliable because of other effects on the repair systems themselves.

Morphological changes during conversion of Clostridium saccharoperbutylacetonicum to protoplasts by sucrose-induced autolysis

When exponentially growing cells of Clostridium saccharoperbutylacetonicum (ATCC 13564) were exposed to hypertonic concentrations of sucrose (0.3--0.5 M), rapid degradation of the cell wall occurred (sucrose-induced autolysis). The morphological changes from the original rod-shaped cells to protoplasts during the sucrose-induced autolysis were investigated by phase contrast and electron microscopy. When the cells were autolysed in the sucrose solution (0.35 M), each cell began to swell at the middle or at one pole and then formed a small bulb at the swollen part. The bulk consisted of the cytoplasm which was enveloped by the plasma membrane and extruded from the small gap produced by the degradation of the cell wall. The bulb gradually enlarged as lysis progressed, and finally became a protoplast which had no cell wall. The large pre-division cell frequently formed the bulb at the middle (septal site), while the small post-division cell formed the bulb at the pole.