Valaciclovir for the suppression of recurrent genital HSV infection: a placebo controlled study of once daily therapy. International Valaciclovir HSV Study Group

OBJECTIVE

To determine the efficacy and safety of once daily valaciclovir for the suppression of recurrent genital herpes simplex virus (HSV) infection in immunocompetent patients.

METHODS

382 otherwise healthy patients with a history of frequently recurring genital HSV infection (eight recurrences per year) were randomly allocated to receive either oral valaciclovir (500 mg once daily) or placebo (3:1 ratio) for 16 weeks or until the first genital HSV recurrence, whichever occurred first. Patients were clinically assessed at regular intervals and also if they experienced a recurrence. Safety was evaluated through adverse experience reporting and monitoring of haematology and biochemistry variables. On completion of the double blind phase, patients were eligible for follow up to a maximum of 48 weeks' treatment with open label valaciclovir (500 mg once daily) for further safety monitoring. The results from the double blind phase of the study are reported here.

RESULTS

A significant difference was detected between valaciclovir and placebo in the time to first recurrence of genital HSV infection. The hazard ratio [95% confidence interval] for valaciclovir v placebo was 0.155 [0.112, 0.214], p < 0.0001. Valaciclovir prevented or delayed 85% of the recurrences that would have occurred with placebo. After 16 weeks (day 112) with treatment, 69% of patients receiving valaciclovir were recurrence free compared with only 9.5% of patients assigned to placebo. The safety profiles of valaciclovir and placebo were comparable, with adverse experiences being infrequent and generally mild.

CONCLUSION

This study has demonstrated that once daily valaciclovir (500 mg), is highly effective and well tolerated for the suppression of recurrent genital HSV infection. Once daily dosing with valaciclovir provides a more convenient dosing regimen than the more frequent aciclovir regimens.

Tumefactive cartilage proliferation after rhinoplasty. A newly reported complication

OBJECTIVE

To describe and document the development of tumoral proliferation of cartilage in 4 patients after nasal surgery, a complication that, to our knowledge, has not been reported before.

DESIGN

Similar postoperative nasal masses were excised from 4 patients who underwent rhinoplasty. Histopathologic evaluation was carried out to identify the nature of the lesions and to provide a basis for rational management of similar lesions subsequently encountered.

SETTING

Academic tertiary referral center.

PARTICIPANTS

Four healthy patients (3 women and 1 man) ranging in age from 21 to 49 years. Two of the patients underwent routine rhinoplasty with resection of cephalic margins of alar cartilages, and 2 underwent augmentation procedures with implantation of auricular cartilage.

INTERVENTION

Discrete firm masses were excised from each patient's nose approximately 1 year after the most recent rhinoplastic procedure was performed. Histological evaluation was carried out on each specimen.

RESULTS

All 4 masses were found to consist of tumefactive proliferation of cartilage. Clonal proliferation and mild nuclear atypia were observed.

CONCLUSIONS

After rhinoplasty, progressive asymmetrical fullness in or adjacent to cartilaginous structures or graft material should suggest the possibility of tumefactive proliferation of cartilage and should be evaluated with surgical exploration. All areas of thickened cartilage should be excised completely, with immediate auricular cartilage reconstruction of resulting anatomical defects. Perichondrium should be completely removed from auricular cartilage implants in the nose, and mechanical injury to the graft should be minimized. We strongly caution against morsellizing dorsal cartilage implants for nasal reconstruction.

Four routes to the future

The following is a synopsis of four potential scenarios for American health care in the year 2005 that were proposed at the most recent Health Care Outlook meeting (see sidebar). These scenarios provided a framework for discussion and debate for MHA's Next Wave Task Force, and a complete report on observations from a Michigan perspective will be made available to the membership soon.

Planning for a community-based hypertension control program in the inner city

Uncontrolled hypertension is a significant problem among African-Americans residing in inner city environments. To help address the problem, we are developing community-based hypertension control programs in African-American communities located in Milwaukee, Wisconsin and Chicago, Illinois. The Milwaukee program focuses on an entire, diverse inner city area, while the Chicago program is targeted to several more homogeneous African-American neighborhoods. The investigators hypothesize that the success of a hypertension control program will depend on carefully tailoring the educational approaches to the specific characteristics of the target area. Therefore, the study areas that have been selected differ with regard to community size and diversity, community 'stressors' (poverty, unemployment, crime, etc), and types of organizations which are present in the community. This paper describes the background and the rationale for community hypertension control programs in the inner city. The initial approaches to establishing the program by developing interfaces with the community and the gathering of baseline data through household surveys are described.

Born in the USA. The medicalization of social problems

As the debate over health care reform intensified a few years ago, Americans questioned their delivery system and pointed to Canada, Great Britain, and other countries as potential models for reform. NHA conducted its own examination of these models and concluded: the United States, and Michigan in particular, will have difficulty improving the health status of its citizens and controlling health care expenditures unless we more effectively deal with a uniquely American phenomenon--the medicalization of social problems.

Glial fibrillary acidic protein and RNA expression in adult rat hippocampus following low-level lead exposure during development

The astroglial cytoskeletal element, glial fibrillary acidic protein (GFAP), is a generally accepted sensitive indicator for neurotoxic effects in the mature brain. We used GFAP as a marker for structural changes in rat hippocampus related to chronic low level lead exposure during different developmental periods. Four groups of rats were investigated: a control group, a perinatal group, which was exposed during brain development (E0-P16), a permanent group, exposed during and after brain development (E0-P100), and a postweaning group, exposed after brain development (P16-P100). Sections were processed for light microscopy (hematoxylin-eosin, Nissl, periodic acid Schiff (PAS) and GFAP-specific immunohistology), for electron microscopy, and for in-situ hybridization (GFAP). Sections were prepared from animals tested for active avoidance learning (AAL) and long-term potentiation (LTP). Chronic lead exposure did not affect glial and neuronal functions, as assessed by LTP and AAL, when lead exposure started after brain development (postweaning group). In this group, astrocytes displayed increased GFAP and GFAP gene transcript levels. However, lead exposure affected neuronal and glial function when the intoxication fell into the developmental period of the brain (perinatal and permanent groups). In these groups, LTP and AAL were impaired, and astrocytes failed to react to the toxic exposure with an adequate increase of GFAP and GFAP gene transcripts. Although GFAP is an accepted marker for neurotoxicity, our data suggest the marker function of GFAP to be restricted to postnatal toxic insult.

A survey in action. The "next wave assessment" takes shape

With the initiation of the Health Care 2000 vision project in 1988, the MHA established itself as one of the first state hospital associations to strategically assess important health care trends and craft a framework for the future of health care delivery and financing for its membership. The 1990s have brought much change and unprecedented challenge to the health care field. As MHA continues to transform to meet the needs of its members, the time has come to reassess our health care environment and critically examine our assumptions about the future.

Abdominal wall hernias in patients with abdominal aortic aneurysmal versus aortoiliac occlusive disease

BACKGROUND

This study was undertaken to determine the incidence of ventral incisional hernias (VIHs) and inguinal hernias (IHs) in patients with abdominal aortic aneurysmal (AAA) versus those with aortoiliac occlusive disease (AIOD).

PATIENTS AND METHODS

The medical records of 193 patients (128 with AAA and 65 with AIOD) who had undergone elective aortic reconstruction were reviewed to determine the number and location of abdominal wall hernias (AWHs).

RESULTS

Forty-one AWHs (28 IHs and 13 VIHs) were detected in patients with AAA compared to 13 (11 IHs and 2 VIHs) in patients with AIOD. There was a significantly greater incidence of VIHs in patients with AAA versus patients with AIOD (10% versus 3%, P < 0.05) and recurrent AWHs (28% versus 19%, P < 0.01), but not of IHs (22% versus 17%).

CONCLUSION

Patients with AAA have a higher incidence of VIHs and recurrent AWHs--without a corresponding increase in patient-related risk factors--than patients without aneurysm, suggesting that as yet unidentified etiologic factors may contribute to the development of AWHs in these patients.

Fragrance administration to reduce anxiety during MR imaging

Fifty-seven outpatients received either heliotropin (a vanillalike scent) with humidified air (n = 20) or humidified air alone (n = 37) via a nasal cannula during magnetic resonance imaging in the diagnostic workup for cancer. Delivery of heliotropin and air was determined by a computer-controlled schedule. Fragrance administration resulted in a statistically significant reduction in average overall patient-rated anxiety (on a visual analog scale) during imaging in patients who found the fragrance moderately to extremely pleasant. Administration of fragrance was associated with 63% less anxiety than administration of humidified air alone. Physiologic measures (pulse and heart rate) did not show a statistically significant effect with fragrance administration.

Protein-DNA interactions in the epsilon-globin gene silencer

The developmental control of expression of the human epsilon-globin gene appears to be mediated, at least in part, by a transcriptional silencer in the DNA 5' to the cap site of this gene. We have used site-directed mutagenesis and DNA-protein binding assays to define the active motifs of this epsilon-globin silencer. DNase I foot-printing of the silencer region with K562 cell nuclear extracts defined a sequence, which we designate as the epsilon-globin silencer motif or epsilon GSM (epsilon -278 to -258 base pairs (bp)) containing a region (epsilon -270 to -258) with 90% homology to the yeast mating type silencer, ABF-1 (autonomous replicating sequence binding factor one) and which also overlaps at (epsilon -269 to -262) with the human YY1 consensus sequence, an element which mediates transcription repression and activation of viral, mouse, and human genes. The DNase I footprint extended 5' in the silencer region to include an inverted repeat of a six-nucleotide motif (epsilon -267 to -278 bp) which shares 5 of 6 bases with the GATA-1 consensus sequence. In gel mobility shift assays, two specific proteins (A and B) in nuclear extracts from erythroleukemia K562 cells bound to the DNase I-footprinted region. Protein B, associated with epsilon-globin silencer activity in vitro, required an intact epsilon GSM sequence for binding. Mutation of 5 bases within the epsilon GSM in an epsilon-globin promoter-containing fragment extending upstream to 1400 bp in transient transfection assays increased activity by 3.0-fold compared with the native sequence, suggesting that the silencer activity was mediated by the epsilon GSM sequence. We found that protein A could be displaced by a competitor containing the GATA-1 consensus sequence, suggesting that protein A is a GATA-like protein. The region from -267 to -271 within the epsilon GSM and GATA-1 homology region was important for binding of both proteins A and B. These data suggest that protein binding to the epsilon GSM and GATA motifs mediate the negative effect of the silencer on transcription, possibly via direct competition for binding to this DNA region. Recombinant yeast ABF-1 and human YY1 bound to the epsilon GSM. Mutating three bases (epsilon -259, -262, -264) in the epsilon GSM decreased the binding affinity of protein B and recombinant human YY1 but increased the binding affinity of recombinant yeast ABF-1. Furthermore, competitor containing the YY1 consensus sequence competed for protein B binding, whereas competitor containing a perfect yeast ABF-1 consensus sequence did not.(ABSTRACT TRUNCATED AT 400 WORDS)

Pneumothorax in patients with AIDS

Eighty-seven inpatients were treated for 93 episodes of Pneumocystis carinii at St Mary's Hospital between January 1989 and December 1990. During this period, 298 patients with the acquired immunodeficiency syndrome (AIDS) were treated at this hospital. Sixteen episodes of pneumothorax occurred and 12 of these, occurring in ten patients, were unrelated to procedure. In six of 12 (50%), the pneumothoraces occurred concurrently with Pneumocystis carinii pneumonia (PCP) and in ten (83%) cases there was a past history of PCP. Bilateral pneumothorax occurred in five cases (42%). In seven (58%) of the cases, patients had been using aerosolized pentamidine as prophylaxis for PCP. This retrospective study confirms the association of pneumothorax with current PCP and also shows an association with previous infection. The use of aerosolized pentamidine was not associated with pneumothorax development. It is important to suspect pneumothorax in a patient with PCP who deteriorates acutely. The high incidence of bilateral pneumothorax means that pleurodesis should be considered early.

Different degree of ileal colonization by segmented, filamentous bacteria in two strains of mice

Segmented, filamentous bacteria (SFBs) are autochthonous, apathogenic inhabitants of the ileum of various animal species. Outbred Swiss (Cpb:SE) mice have significantly higher degrees of SFB colonization than do inbred BALB/c mice. The present studies were carried out to identify determinants of this strain difference. In a cross-fostering experiment it was shown that SFB colonization of the pups is determined by the strain of the pups themselves rather than by the strain of the nursing dam. Thus, maternal effects may not be involved in SFB colonization. In a cross-infecting experiment using germ-free and SFB-positive animals of the two mouse strains, it was found that ileal SFB colonization is determined by host characteristics rather than by origin of the SFBs. Thus, SFBs that are specific for a given mouse strain may not exist in the two strains of mice. It is concluded that the mouse strain difference in SFB colonization is determined by host characteristics, which probably have a genetic basis.

Kaposi's sarcoma in HIV infection treated with vincristine and bleomycin

OBJECTIVE

To evaluate the efficacy and toxicity of vincristine and bleomycin when used in combination to treat patients with progressive Kaposi's sarcoma.

DESIGN

A retrospective case notes review.

SETTING

The departments of Immunology and Genito-Urinary Medicine, St Mary's Hospital, London, UK.

PATIENTS

All patients presenting with progressive Kaposi's sarcoma and requiring chemotherapy between January 1987 and January 1990, who had received no previous systemic chemotherapy.

INTERVENTIONS

Treatment with vincristine (2 mg) and bleomycin (30 mg, 18 h infusion), or vinblastine (2.5-5.0 mg) if peripheral neuropathy developed. Treatment with zidovudine and prophylaxis of opportunistic infections where indicated.

OUTCOME MEASURES

Response, toxicity and survival.

RESULTS

Overall, patients had a poor prognosis: 33 out of 46 (72%) had had a previous opportunistic infection, had a mean CD4 count of 144 x 10(6) (20 out of 46 tested) and a mean Karnofsky index of 75.4. They received a median of five cycles of therapy: a partial response was achieved in twenty-six patients (57%), disease progression was halted in a further 16 (35%), while disease progression continued in four (9%) despite therapy; there were no complete responders. Mean duration of response was 2 months (s.d., 1.26 months), survival was 8 months (s.d., 6.7 months) from start of therapy and 17 months (s.d., 8.9. months) from first AIDS diagnosis. On multivariate analysis the best predictor of mortality was the presence of previous opportunistic infection (P = 0.00653). Side-effects were minimal in comparison with other studies. The most common side-effect, in 13 cases (28%), was peripheral neuropathy, which may in part represent the prevalence of HIV neuropathy or remain as background. Haematological toxicity was uncommon.

CONCLUSIONS

Treatment for HIV-related Kaposi's sarcoma in advanced HIV disease is becoming more necessary as disease profiles change. Conventional chemotherapy regimens for malignancy are not well tolerated in these patients and may not be indicated. This regimen is effective and has low toxicity in AIDS patients. Non-responders should be considered for more intensive regimens.

A phase II study of sulofenur (LY186641) in gastric cancer

Sulofenur is a novel diarylsulfonylurea with proven anti-tumor activity in murine tumor models. In this phase II study in patients with advanced gastric or gastroesophageal adenocarcinoma, 17 patients were treated with sulofenur orally at 700 mg/m2 for 14 days every 3 weeks. No tumor responses were seen. The main toxicities were anemia, methemoglobinemia and abnormalities in liver function tests. These toxicities precluded dose escalation. However, plasma levels of sulofenur, and its hydroxy and keto metabolites were probably insufficient to exert anti-tumor effect in comparison with data from murine studies. Further structure-activity studies are warranted.

The epsilon-globin gene silencer. Characterization by in vitro transcription

K562 human erythroleukemia cells constitutively express epsilon- and gamma- but not beta-globin genes. We have previously shown that the differential expression of globin genes observed in intact K562 cells could be simulated in vitro as K562 nuclear extract (NE) actively transcribes the epsilon-globin (with 2 kilobases of 5'-flanking sequence) and gamma-globin gene DNA templates but not beta-globin gene templates. We have now used the K562 in vitro transcription system to examine a silencer transcriptional control element which has been reported to be localized between -177 and -392 base pairs (bp) 5' of the canonical cap site for the epsilon-globin gene. We find that K562 NE has markedly reduced synthesis of RNA in vitro from epsilon-globin gene DNA deletion templates which contain the silencer sequence, or part thereof, but not the adjacent 5'-positive regulatory region (-453 to -535 bp). Furthermore, those transcripts generated in vitro from DNA templates extending to -453 bp or less of the epsilon-globin gene were not correctly initiated at the canonical cap site. Separating the K562 NE by ion exchange chromatography, we isolated a fraction (F175) transcriptionally active for all tested globin genes including the epsilon-globin gene containing the silencer sequence and a fraction (F50) which contains the trans-acting factors associated with the silencer activity. F50 showed a strong dose-dependent inhibitory effect on correctly initiated epsilon-globin gene transcription directed by either unfractionated K562 NE or F175. This suppression by F50 was not observed on transcriptional activity of the permissive adenovirus 2 major late promoter. In electrophoretic mobility shift assays using the epsilon-globin gene silencer region as probe, F50 and F175 exhibited different DNA binding protein patterns; a specific protein band in F50 appears to be associated with the silencer activity. These studies suggest that this protein may be specifically responsible for the activity of the silencer element of the epsilon-globin gene. The expression and silencing of the epsilon-globin gene during development may be modulated by the interactions of this protein with the cis-acting DNA silencer.

[Mycobacterium kansasii seroma of the skin in HIV infection]

We report on an HIV-infected patient with AIDS in whom a smoothly demarcated area of resistance in the size of a fist was found on the inside of the thigh. Investigation by sonography for clinical differential diagnosis confirmed that a haematoma, a seroma or an abscess might be present. Upon puncture of the cavity, serous exudate was obtained. The microbiological investigation resulted in the growth of Mycobacterium kansasii. The detection of this agent in throat and sputum samples from the patient and the occurrence of an osteomyelitis lesion at the same time indicate that the seroma was a partial manifestation of a disseminated Mycobacterium kansasii infection. No indications of a transcutaneous route of infection was found. Upon antimicrobial chemotherapy after the determination of resistance the seroma disappeared.

A phase II study of sulofenur, a novel sulfonylurea, in recurrent epithelial ovarian cancer

A total of 16 patients with recurrent epithelial ovarian cancer were treated with sulofenur (LY 186641), a novel oral sulfonylurea. All subjects had received previous chemotherapy. Anaemia occurred in all 16 patients, 14 of whom required a blood transfusion, and 2/16 patients received methylene blue for breathlessness due to methaemaglobinaemia. Treatment was discontinued in 2/16 cases due to rising liver enzyme values, which reverted to normal on cessation of the drug. There was no nausea or alopecia. Only two minor responses were seen. Plasma drug levels were insufficient to result in antitumour activity as extrapolated from animal data. Further studies that attempt to increase the bioavailability and improve the therapeutic index are warranted.

A protective thermoplast splint for the forearm and hand in nonhuman primates

A custom-made thermoplastic splint was developed for the protection of the upper extremity after experimental surgery. It was used in 39 cases for a duration of 12-79 days. Complications were minimal and transient. The cast was easy to make, in one piece and inexpensive. Frequent removal for wound inspection was simple. This splint provides a good immobilization and protection of the arm and hand in the nonhuman primate.

A trial with a new peripheral implanted vascular access device

In a prospective study, a new implanted vascular access device designed for peripheral placement in the arm was evaluated. Thirty-two patients requiring long-term venous access received the Port-A-Cath P.A.S. Port over a 13-month period. The access devices were used for multiple therapies including chemotherapy, antibiotics, antivirals, antifungals, and blood products. After 4,896 patient days (range 12-388), 19 complications occurred in 14 patients or 3.88/1,000 catheter days. The infection rate was 3% or 0.2/1,000 catheter days. Port pocket cellulitis was reported in 3% of patients or 0.2/1,000 catheter days. Vein phlebitis occurred at 12.5% or 0.8/1,000 catheter days. Two instances of vessel thrombosis occurred (6.2% or 0.4/1,000 catheter days). Ten incidents in six patients of inability to aspirate blood samples were noted (18.75% or 2/1,000 catheter days). No infiltrations or extravasations were reported. Nurses involved in this early trial found performance similar to the standard venous chest ports. Peripheral port placement was accepted well by patients.

Micronucleated erythrocytes as an index of cytogenetic damage in humans: demographic and dietary factors associated with micronucleated erythrocytes in splenectomized subjects

Erythrocytes containing micronuclei serve as an indicator of genotoxic exposure in splenectomized individuals. Micronucleated erythrocytes, derived from cytogenetically damaged RBC precursors, are not selectively removed from peripheral blood in individuals who lack splenic function. The relationship between micronucleated cell frequencies and demographic, environmental, and dietary factors was examined in 44 subjects with previous splenectomy due to trauma. Their micronucleated cell counts fit a log-normal distribution, with geometric means of 3.3 micronucleus-containing cells/1000 reticulocytes and 2.7/1000 normochromatic erythrocytes. A multiple regression analysis showed that drinking five cups of coffee or tea/day (relative to none) was associated with an approximately 2-fold higher frequency of micronucleated cells. Weaker statistical associations were also noted with micronucleus frequency and the consumption of calcium supplements (associated with a higher frequency) and vitamins A, C, or E (lower frequency). An apparent trend of higher micronucleus counts with age was attenuated when other factors were considered in the regression. Cigarette smoking and decaffeinated coffee consumption were among the factors not associated with elevated micronucleated cell frequencies. Because the occurrence of micronuclei in reticulocytes reflects cytotoxic exposures within the past 3-8 days, it may be possible to test directly the relationship of these factors to micronucleus formation through intervention studies.

Pulmonary cavitation with Nocardia and Aspergillus in a renal transplant patient

We present an autopsy case of concomitant pulmonary aspergillosis and nocardiosis undiagnosed during life in a long-term surviving renal transplant recipient. The patient had fever and a newly developed cavitary lesion on a chest x-ray. The working diagnosis was pulmonary tuberculosis with possible colonization by Aspergillus species. Cultures of bronchial washings became positive for Aspergillus fumigatus 1 day after death. The study of tissue from the lung cavity at autopsy revealed Aspergillus fumigatus (confirmed by postmortem culture) and the filaments of Nocardia species. Increased numbers of surviving immunosuppressed patients will require aggressive, comprehensive diagnostic techniques for the detection of polymicrobial infections.

Staff carriage of epidemic methicillin-resistant Staphylococcus aureus

Twenty-six nurses were repeatedly screened for carriage of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) immediately before and after duty periods in which they solely attended six patients widely colonized with two EMRSA strains distinguishable by plasmid analysis. EMRSA carriage was detected in 13 nurses. Three EMRSA carriage patterns emerged: transient carriage in 12 nurses, when the EMRSA was isolated from noses or fingers of nurses after duty but was gone before their next day's duty; short-term nasal carriage, seen on occasion in 4 of these 12 nurses, when EMRSA carriage was detected on two consecutive screens; and persistent nasal carriage, seen in 1 nurse only, when the EMRSA was seen on more than two consecutive occasions. All but one of these incidents of carriage could be explained by close patient, rather than environmental, exposure and occurred despite an intensive control programme. Transient or short-term carriage in nurses probably resulted in transfer of the EMRSA between patients. Staff decontamination should be considered following a period of cohort nursing of EMRSA patients, especially if staff members are shortly to nurse unaffected patients. Our findings may explain some of the difficulties in controlling EMRSA.

Immunoradiometric assay of carcinoembryonic antigen with use of avidin-biotin labeling

In evaluating an enzyme-linked immunoassay of carcinoembryonic antigen (CEA) we found that the IgG fraction of polyclonal anti-CEA antibodies (DAKO) bound very well to the walls of polypropylene test tubes. We therefore developed an immunoradiometric CEA assay based on this binding of polyclonal anti-CEA antibody. We biotinylated a commercially available monoclonal antibody (Hybritech) and bound this to the CEA-anti-CEA bound to the tube wall. For detection we used 125I-labeled streptavidin. In comparison with several immunoassays for CEA this system offered several advantages such as greater linearity of the standard curve (from 0 to 74 micrograms/L), a steeper dose-response curve, and smaller coefficients of variation in the clinically useful range. This assay system may be used for other large molecules, so that only one tracer, the 125I-labeled streptavidin, has to be labeled; thus the technique seems suited for several different assays.

An asymmetric field inversion gel electrophoresis method for the separation of large DNA molecules

An electrophoretic method for separating large DNA molecules which uses periodically inverted electric fields of different magnitude in the two directions is described. Net DNA migration is either in the high field direction or in the low field direction, depending on the relative duration of the pulses. With this approach, molecules of up to 1.6 million base pairs can be separated in parallel lanes after a single run under fixed timing conditions. An inexpensive switching unit is the only device needed in addition to the conventional gel box.

Immunoradiometric assay of carcinoembryonic antigen with use of avidin-biotin labeling

In evaluating an enzyme-linked immunoassay of carcinoembryonic antigen (CEA) we found that the IgG fraction of polyclonal anti-CEA antibodies (DAKO) bound very well to the walls of polypropylene test tubes. We therefore developed an immunoradiometric CEA assay based on this binding of polyclonal anti-CEA antibody. We biotinylated a commercially available monoclonal antibody (Hybritech) and bound this to the CEA-anti-CEA bound to the tube wall. For detection we used 125I-labeled streptavidin. In comparison with several immunoassays for CEA this system offered several advantages such as greater linearity of the standard curve (from 0 to 74 micrograms/L), a steeper dose-response curve, and smaller coefficients of variation in the clinically useful range. This assay system may be used for other large molecules, so that only one tracer, the 125I-labeled streptavidin, has to be labeled; thus the technique seems suited for several different assays.

ELISA for human pancreatic elastase 1

A sandwich-type ELISA for human pancreatic elastase 1 was developed and assessed for clinical feasibility. Using highly purified reagents, the test seems to be as sensitive and specific as the well-documented Radio-immunoassay (RIA) for the detection of elevated elastase 1 serum levels and, consequently, would have the same indications described for the RIA. In addition, the ELISA could be valid as a screening test for cystic fibrosis. Because ELISA reagents are relatively stable, the assay is always ready to use and can be performed without special equipment.

A prospective, randomized study comparing transparent and dry gauze dressings for central venous catheters

Patients having central venous catheters for three or more days were prospectively randomized to receive a transparent (n = 58) or gauze (n = 57) dressing to compare the incidence of insertion site colonization, local catheter-related infection, and catheter-related sepsis. Quantitative cultures of the catheter insertion site (25 cm2) revealed significantly greater colonization (P less than or equal to .009) after 48 h in the transparent versus the gauze dressing group. Local catheter-related infection occurred significantly more often (P = .002) in the transparent (62%) than in the gauze group (24%). Seven episodes of catheter-related bacteremia occurred in the transparent group (16.6%) and none in the gauze group (P = .015). Stepwise logistic regression analysis revealed that cutaneous colonization at the insertion site of greater than or equal to 10(3) cfu/mL (relative risk, 13.16) and difficulty of insertion (relative risk, 5.39) were significant factors for catheter-related infection. These data suggest that transparent dressings are associated with significantly increased rates of insertion site colonization, local catheter-related infection, and systemic catheter-related sepsis in patients with long-term central venous catheters.

Ultrastructural identification of Merkel cells around the mouth of the newborn marsupial

The ultrastructure of the epidermal cells surrounding the mouth of three newborn marsupial species, the Northern native cat Dasyurus hallucatus, the brush tail possum Trichosurus vulpecula and the Northern brown bandicoot Isoodon macrourus were examined. The presence of Merkel cells, highly sensitive touch receptors, would suggest that the sense of touch aids the relatively underdeveloped newborn marsupial to move from the urinogenital sinus to the pouch and to locate the teat.

Isolation and characterization of bleomycin-sensitive Chinese hamster ovary cells

Nineteen bleomycin-sensitive Chinese hamster ovary cell mutants have been isolated using a replica plating and photography approach. As judged by the dose which reduces cell survival to 37% of the untreated control, these mutants are from 2.5- to 32-fold more sensitive to a 16-h bleomycin treatment than the parental cell, while for chronic bleomycin exposure, the increase in sensitivity was 5 to 58 times that of the parental cell. Four bleomycin-sensitive mutants had increased sensitivities to killing by gamma-rays (2- to 3-fold), mitomycin C (2-fold), and ethyl methane sulfonate (4- to 5-fold), while six other mutants were resistant to these agents. Nine other bleomycin-sensitive mutants displayed a variable pattern of cross-sensitivities to these agents. Using the technique of alkaline elution, the relative frequency of single-strand DNA breaks introduced by varying concentrations of bleomycin was examined in one mutant and its parent cell. The elution profiles of both cells were similar, suggesting that the bleomycin sensitivity of this mutant is not due to a greater frequency of single-strand breaks introduced by bleomycin.

Delayed mutation in Chinese hamster cells

The possibility was examined that mutational events can be delayed for more than one or two cell divisions following treatment of Chinese hamster cells with the DNA alkylating agent ethyl methane sulfonate. If mutations in mammalian cells are delayed, the proportion of mutant cells in colonies grown from single mutagen-treated cells will reflect the cell division at which the mutation is genetically fixed, i.e., a first division mutation yields a 1/2 mutant colony, a fifth division mutation produces a 1/32 mutant colony, etc. In the present study, replating of cells from single colonies grown for six to seven days after mutagen treatment resulted in the discrete ratios of glucose-6-phosphate dehydrogenase (G6PD)-deficient mutant to wild-type colonies expected for a delayed mutational process which produces mutations over at least 8-10 cell generations. Further, when cells from 7- to 10-day colonies, grown from ethyl methane sulfonate (EMS)-treated cells were replated into selective medium containing 6-thioguanine (6TG), the number of 6TG-resistant colonies obtained per flask was distributed over a very wide range, consistent with a mutational delay process. These results could not be explained by differences in the number of cells per colony or plating efficiency in selective medium. Assuming that the relative number of 6TG-resistant colonies per flask reflects the time of mutation, EMS treatment produced two groups of mutational events: one which occurred within the first five cell generations and another uniformly distributed over at least the next eight to nine divisions. These results support the conclusion that EMS induces mutants for at least 10-14 cell generations after treatment and raise the possibility that current methods to assess the mutagenic potential of an agent might lead to significant underestimation. The role of delayed mutation in the phenomenon of "mutation expression time" is also discussed.

Portable emergency ventilators. 2. Sensitivity to environment

Three compact ventilators (Oxylog, Maxaman and Pneupac 2), commercially available in Sweden, were subjected to tests concerning sensitivity to environmental stress. The ventilators functioned very well at temperatures above 0 degree C. The Oxylog apparatus was very sensitive to subzero temperatures. It also had a spectrum of resonance frequencies when subjected to vibration testing that restricts its use outside the sheltered hospital environment. The Maxaman and Pneupac 2 in the modified version withstood the tests in a reliable way. The shock tests performed had no negative effects on any of the ventilators or their functions.