In-vitro effects of cefodizime on leucocyte functions and colony formation from granulocyte-monocyte progenitors

Infections in immunocompromised patients are often difficult to treat, even with currently available antimicrobial agents. An understanding of the effects of antibiotic therapy on the host's immune response is therefore important when deciding on the clinical management of such patients. Antimicrobial agents which lack immunodepressive effects and/or potentiate the immune response are the goal of current research into the treatment of infections in immunocompromised patients. The effects of cefodizime (1-250 micrograms/mL) in vitro on some functional activities of leucocytes and on colony formation by granulocyte monocyte progenitors were studied to investigate the effects of the antibiotic on the host's immune response. A marked enhancement in the lymphocyte transformation reaction was observed in cells exposed to cefodizime. This effect was dose-dependent. Cefodizime had no significant effect on antibody-dependent cell cytotoxicity or on natural killer cell-mediated cytotoxicity. The chemotactic activity of neutrophils was not influenced by the presence of cefodizime (P > 0.05). The phagocytic activity of neutrophils was significantly increased by cefodizime (P > 0.01). Cefodizime significantly stimulated, in a dose-dependent manner, colony formation by granulocyte-monocyte progenitors (P < 0.01). Results suggest that cefodizime has certain stimulatory effects on immunocompetent cells such as enhancing the transformation reaction of lymphocytes, neutrophil phagocytosis and colony formation by granulocyte-monocyte progenitors. Further studies are required to clarify the mechanisms responsible for these effects.

Immunogenicity of Vi capsular polysaccharide vaccine evaluated for three years in Korea

The immunogenicity of a single dose of Salmonella typhi(S.typhi) Vi capsular polysaccharide(CPS) vaccine was evaluated before, and at 1, 3, 12, and 36 months after vaccination. Eighty-five adults(20-28 years of age) and sixty-four children(8-16 years of age) received a single dose of 25 micrograms Vi CPS vaccine intramuscularly, and antibody titers to Vi CPS were measured by passive hemagglutination. Of 149 vaccinees, 138(92.6%) showed seroconversion at 1 month after vaccination, and then 138 out of 141(97.9%) did at 3 months. Of 137 vaccinees, 116(84.7%) maintained a persistent rise in Vi antibody titer 12 months after vaccination, and 55 out of 100(55.0%) had a 4-fold or greater rise at 36 months. No significant adverse reactions were observed. Booster injection may be needed 3-5 years after vaccination.

Two human cases of Thelazia callipaeda infection in Korea

Thelazia callipaeda were observed from a 7-month old baby who lived in Uijongbu in 1989 and from a 42-year old man who lived in Anyang in 1994. These are the 23rd and 24th records of human thelaziasis in Korea as the literature are concerned.

Stability testing of a two miniplate fixation technique for mandibular angle fractures. An in vitro study

In the case of mandibular angle fractures, a two miniplate fixation technique in which one plate is applied ventral to the oblique line and a second plate at the inferior border of the buccal cortex was used to stabilize the fracture. In this paper, the stability of the two miniplate fixation technique was tested in a three-dimensional in vitro model. The results of this study showed that in cases of angle fractures this fixation technique provides stable fixation under functional loading.

Five cases of cytomegalovirus infection detected by in situ hybridization and antigenemia assay

We report five cases of cytomegalovirus infection in immunocompromised patients which were detected by either cytomegalovirus antigenemia assay or in situ hybridization. Four cases had leukemia and the other had chronic renal failure. All the three BMT recipients suffered from GvHD. Interestingly, there was an unique case of CMV disease without a history of BMT, which reminded us that CMV could attack immunocompromised patients who had not undergone transplantation, too. Four out of five cases died. We think that cytomegalovirus infection or disease should not be regarded as a minor problem in post-transplantation infection in Korea.

Testosterone regulation of proto-oncogene c-myc expression in primary Sertoli cell cultures from prepubertal rats

The expression of c-myc has been associated with cell proliferation through changes of nuclear function. To evaluate the possibility that the proto-oncogene c-myc plays a role in testosterone-dependent gene regulation, the effects of testosterone on the expression of c-myc have been investigated in primary Sertoli cell cultures. Testosterone increased c-myc mRNA levels, with maximal stimulation reached in 16 hours. The induction of c-myc mRNA was dependent on the concentration of testosterone. Testosterone-induced c-myc mRNA levels were also increased in cells after addition of cycloheximide but reduced by actinomycin-D pretreatment. Even in the absence of hormone in culture medium, c-myc mRNA was clearly detectable in Sertoli cells from 8-day-old rats but hardly detectable in cells from 14 and 28 days of age. Testosterone stimulated c-myc mRNA expression in the Sertoli cells from only 8-/and 14-day-old rats. These results suggest that testosterone induces c-myc mRNA levels in the primary Sertoli cells from prepubertal rats, and then transient expression of c-myc may be responsible for some of the regulatory roles of testosterone-dependent genes in the Sertoli cells. The biological significance of testosterone-dependent c-myc induction is not known.

Comparison of magnetic resonance imaging before and after nonsurgical treatment of closed lock

Ten temporomandibular joints with the closed lock in 10 patients who were successfully treated clinically nonsurgically with the occlusal splint, were studied with magnetic resonance imaging. In all patients, the pretreatment images of temporomandibular joints showed anteriorly dislocated disks that failed to recapture together with various changes in disk morphology. Three to four months after the treatment, all patients could open their mouths more than 47 mm at the incisor position and were asymptomatic. But the follow-up magnetic resonance images showed that the disks were still anteriorly displaced and deformed and their relationships with the condyles were unchanged. The reestablishment of mouth opening appeared to occur not by recapturing of the disks but by improvement in condylar mobility and the adaptation of the posterior attachment.

A case of bullous transient acantholytic dermatosis

We report a case of a bullous variant of transient acantholytic dermatosis in a 59-year-old female. Each bullous lesion lasted several weeks and healed without scarring. The lesions were migratory and recurrent without a cleared period. Histopathologic examination revealed an intraepidermal vesicle low in the epidermis. The lesions cleared after 2 months of isotretinoin therapy.

Vulnerability of the human airway epithelium to hyperoxia. Constitutive expression of the catalase gene in human bronchial epithelial cells despite oxidant stress

Although catalase is a major intracellular antioxidant, the expression of the human catalase gene appears to be limited in the airway epithelium, making these cells vulnerable to oxidant stress. The basis for this limited gene expression was examined by evaluation of the expression of the endogenous gene in human bronchial epithelial cells in response to hyperoxia. Hyperoxia failed to upregulate endogenous catalase gene expression, in contrast to a marked increase in expression of the heat shock protein gene. Sequence analysis of 1.7 kb of the 5'-flanking region of the human catalase gene showed features of a "house-keeping" gene (no TATA box, high GC content, multiple CCAAT boxes, and transcription start sites). Transfection of human bronchial epithelial cells with fusion genes composed of various lengths of the catalase 5'-flanking region and luciferase as a reporter gene showed low level constitutive promoter activity that did not change after exposure to hyperoxia. Importantly, using a replication-deficient recombinant adenoviral vector containing the human catalase cDNA, levels of catalase were significantly increased in human airway epithelial cells and this was associated with increased survival of the cells when exposed to hyperoxia. These observations provide a basis for understanding the sensitivity of the human airway epithelium to oxidant stress and a strategy for protecting the epithelium from such injury.

Protection of human endothelial cells from oxidant injury by adenovirus-mediated transfer of the human catalase cDNA

In a variety of disorders, endothelial cells are exposed to high levels of oxidants, generated within the cells and/or consequent to local inflammation. In the context of the sensitivity of endothelial cells to oxidant stress, particularly related to H2O2, we have designed a replication deficient recombinant adenovirus containing the human catalase cDNA (AdCL) to transfer the catalase cDNA to the endothelial cells, in order to augment intracellular anti-H2O2 protection. Human umbilical vein endothelial cells that were not infected or infected with control adenovirus maintained low levels of catalase mRNA. Endothelial cells infected with AdCL expressed AdCL-driven exogenous catalase mRNA, as early as 24 hr and at least for 7 days. Catalase protein levels were increased significantly over controls in cells infected with AdCL, as were catalase activity levels, with catalase activity correlated closely with levels of catalase protein. Importantly, when the endothelial cells were exposed to 500 microM H2O2, all the AdCL infected endothelial cells survived, compared to only 37% of the control cells. Thus, a recombinant adenovirus containing the human catalase cDNA is able to infect human endothelial cells in vitro and express high levels of functional intracellular catalase, protecting the cells against H2O2-mediated oxidant stress. These observations support the feasibility of the transfer of catalase cDNA to human endothelium to protect against oxidant injury.

Evidence for the multistep nature of in vitro human epithelial cell carcinogenesis

In keeping with the multistep development of human cancer in vivo, a stepwise approach to neoplastic transformation in vitro presents a reasonable strategy. We have recently developed an in vitro multistep model suitable for the study of human epithelial cell carcinogenesis. Upon infection with the adenovirus 12-simian virus 40 hybrid virus, primary human epidermal keratinocytes acquired an indefinite life span in culture but did not undergo malignant conversion. Subsequent addition of Kirsten murine sarcoma virus and human ras oncogene or chemical carcinogens (N-methyl-N'-nitro-N-nitrosoguanidine or 4-nitroquinoline 1-oxide) to these cells induced morphological alterations and the acquisition of neoplastic properties. Subsequently it was found that this line could be transformed neoplastically by a variety of retrovirus-containing H-ras, bas, fes, fms, erbB, and src oncogenes. In addition, we found that the immortalized human epidermal keratinocyte (RHEK-1) line can be transformed neoplastically by exposure to ionizing radiation. Thus, this in vitro system may be useful in studying the interaction of a variety of carcinogenic agents and human epithelial cells. These findings demonstrate the malignant transformation of human primary epithelial cells in culture by the combined action of viruses, oncogenes, chemical carcinogens, or X-ray irradiation and support a multistep process for neoplastic conversion.

Technetium-99m red blood cell blood-pool imaging in functional asplenia due to leukemic infiltration

Tc-99m labeled RBC blood-pool and Tc-99m sulfur colloid imaging were performed in a patient with chronic myelogenous leukemia (CML) in blast crisis. Functional asplenia was demonstrated on the sulfur colloid study despite intact organ perfusion as demonstrated by blood-pool imaging. Tc-99m RBC blood-pool imaging appears to be an ideal noninvasive technique to document intact spleen perfusion in functional asplenia.

Hemivertebral "disappearance" on bone scan

Two cases are described in which there was absence of uptake in hemivertebra on a Tc-99m methylene diphosphonate bone scan. In one of these patients, the bone image had been normal 56 days previously. Radiographs of the vertebrae were normal in both cases. Data are presented suggesting that the findings can most probably be explained in terms of compromise of blood supply to the hemivertebra; each half of a vertebra usually has a separate arterial contribution.

Quantitative measurement of body motion using Schottky barrier silicon photodiode

A new motion detection system has been developed using a laser beam and a Schottky barrier silicon photodiode. The system broadens the scope of gravitational center stabilography by facilitating the quantitative assessment of tremors of body appendages such as the hands and even the head. The system also eliminates cumbersome platforms and wire attachments previously used in gravitational center stabilography. The subject is asked to aim the beam at the photodiode. A quantitative off-center variation parameter, ARDS (Average Radial Distance Squared multiplied by time), was utilized in units of cm2 sec. A preliminary evaluation of the system shows that it is suitable for rapidly screening large numbers of subjects for localised neuromuscular control.

Development of instruction in hospital electrical safety for medical education

Although hospital electrical safety is receiving increased attention in the literature of engineers, it is not, at present, reflected in the curricula of medical schools. A possible reason for this omission is that biomedical and/or clinical engineers knowledgeable in electrical safety are not usually trained to teach. One remedy for this problem is to combine the knowledge of engineers with that of instructional developers to design a systematic curriculum for a course in hospital electrical safety. This paper describes such an effort at the University of Texas Health Science Center at San Antonio (UTHSCSA). A biomedical engineer and an instructional developer designed an instructional module in hospital electrical safety; the engineer taught the module, and both evaluated the results. The process and outcome of their collaboration are described. This model was effectively applied in the classroom as a four-hour segment in hospital electrical safety for first-year medical students at UTHSCSA. It is hoped that an additional benefit of this system will be that it offers an opportunity for continuing improvement in this kind of instruction at other medical schools and hospitals.

An alternative approach to hospital electrical safety

In the past, the only acceptable method for protecting hospital patients against the hazards of macroshock and microshock was equipotential grounding: a system whereby potential differences between conductive surfaces are minimized, and ground loops are eliminated, through use of a network of grounding conductors connected in a tree-branch configuration to a common reference point. Experience at a major medical facility involving attempts to create and maintain an equipotential grounding system has proven this method to be costly, impractical, and potentially hazardous. Recent improvements in the input circuitry of medical instrumentation and the rapid disappearance of explosive anesthetics from many hospital inventories now make it possible to suggest an alternative approach to electrical safety: the insulated environment.

Human skin burns induced by defibrillator default current: a mathematical simulation model

A preliminary model was prepared for the development of superficial burns which can result from the interaction of faulty defibrillator and other electrical operating room equipment. A thermal model previously used to predict retinal coagulation was adapted to give temperature rise history of the skin. Skin resistance is assumed to decrease rapidly due to the instability of a small volume near the surface. Heating due to dissipation of the defibrillator capacitor energy in this skin volume is shown to be high enough to cause burns. A sensitivity analysis is included to isolate the dominant input parameters. Recommendations are made for future research.

Human skin burns induced by defibrillator default current

The attachment of various types of electronic instrumentation to a patient can lead to hazardous interactions. Component malfunction in a single piece of equipment connected to a patient may be totally innocuous. However, the same fault occurring in an identical piece of equipment functioning as one component in a network of monitoring and electrosurgical equipment can result in severe burns or even electrocution. This paper describes interaction between a defective defibrillator paddle and an electrosurgical unit. Burns and ventricular fibrillation resulting from this malfunction and interaction are described in detail and the electrical circuits are analyzed.