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Biomedical subjects

D H Martin

Publications and source records attributed to D H Martin.

107 records · Page 6Linked to original sources
PubMed1972

Field studies of an attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83).

A series of field studies using strain TC-83 attenuated Venezuelan equine encephalomyelitis vaccine in horses was made to determine the rate of seroconversions, the postvaccination viremia, and the possibility of adverse reactions to the vaccine. The rate of seroconversions varied from 50% in one study to 91 and 100% in two others. The highest level of viremia measured was 7 x 10(3) to 8 x 10(3) plaqueforming units per ml. No adverse reactions to the vaccine were observed in any horses, including 42 pregnant mares and their resulting foals.

Animals↗
PubMed1969

Isoaccepting transfer RNA's of L-M cells in culture and after tumor induction in C3H mice.

Co-chromatography in a reversed-phase column was performed for 16 aminoacyl-tRNA's prepared from L-M cells grown in serum-free suspension culture and from tumors induced in irradiated C(3)H mice by subcutaneous injection of L-M cells. The results showed that between the two sources there were (1) marked differences in aspartyl-, histidyl-, phenylalanyl-, and tyrosyl-tRNA's; (2) significant quantitative differences in isoaccepting species of alanyl-, isoleucyl-, seryl-, and threonyl-tRNA's; and (3) similar to minimally different patterns of arginyl-, methionyl-, prolyl-, tryptophanyl-, valyl-, glycyl-, leucyl-, and lysyl-tRNA's. The differences were evident when synthetases prepared either from L-M cells or from the tumors were used. When the L-M tumors were brought back into in vitro culture, their tRNA patterns were like those of L-M cells. Addition of serum to the culture medium caused the L-M cells to show very minute, but detectable, amounts of the isoaccepting tRNA's found in the tumors. The cellular mechanisms which may be related to the changes of tRNA patterns in the L-M cells are discussed.

Alanine↗
PubMedDate not supplied

In-vitro and in-vivo activity of parenterally administered beta-lactam antibiotics against Chlamydia trachomatis.

The extended-spectrum penicillins ticarcillin, mezlocillin, and piperacillin might be useful as single agents for the treatment of pelvic infections in women if it could be shown that these drugs are active against Chlamydia trachomatis. We found that the MIC90 (concentration at which 90% of strains are inhibited) values of ticarcillin, mezlocillin, and piperacillin were 16, 16, and 64 micrograms/ml, respectively. Several cephalosporins were found to have MICs for C. trachomatis of greater than 200 micrograms/ml. Ten women with postpartum endometritis who were colonized with C. trachomatis had repeated chlamydial cultures following treatment with beta-lactam antibiotics. All seven cases treated with ticarcillin plus clavulanic acid (a beta-lactamase inhibitor) or piperacillin alone had C. trachomatis-negative cultures after treatment. Three of four of these women had negative cultures at a second follow-up visit. In contrast, the three women treated with a cephalosporin were culture-positive at their first follow-up clinic visit. These data suggest that there is a correlation between the in-vitro measurement of beta-lactam antibiotic activity against C. trachomatis and the microbiologic outcome of treatment. We conclude that the extended-spectrum penicillins deserve further evaluation as single agents for the treatment of pelvic infections in women at high risk for C. trachomatis infections.

Adult↗
PubMedDate not supplied

High syphilis rates among cocaine abusers identified in an emergency department.

The recent syphilis epidemic in the United States has been linked to cocaine abuse. The goal of this study was to estimate the prevalence of newly diagnosed latent syphilis, as well as previously treated syphilis, in emergency department patients giving a history of cocaine use. Charity Hospital emergency department patients without symptoms of sexually transmitted disease (STD) who admitted to cocaine use were enrolled and screened for syphilis with the automated reagin test (ART). Patients were questioned about past syphilis episodes, sexual behavior, and drug use patterns. Reactive ARTs were confirmed with the microhemagglutination antibody to Treponema pallidum (MHA-TP) or the fluorescent treponema antibody-absorbed (FTA-ABS) test. Additionally, treponemal tests were performed in 68 of 79 ART-negative patients. Twenty-four women and 78 men were included in the sample over the 6-month period from December 1989 through May 1990. Of those enrolled, 64% used crack, only 24% were exclusively intravenous users, and 6% were exclusively nasal users. The remaining 6% utilized multiple routes of drug administration. Nine latent syphilis patients (8.8%) were diagnosed and an additional 20 (19.6%) patients were found to have had previous syphilis. Among the 24 women studied, 5 (20.8%) had latent syphilis. Fifty-eight percent of women had either latent or previously treated syphilis as compared to 19% of men (P = 0.0006). These data suggest that elicitation of a history of cocaine use from urban hospital emergency department patients may be helpful in identifying patients with latent syphilis. Detection and treatment of latently infected women in this setting could prevent a significant number of congenital syphilis cases.

Adolescent↗
PubMedDate not supplied

Development of a polymerase chain reaction assay for the detection of Haemophilus ducreyi.

BACKGROUND AND OBJECTIVES: Haemophilus ducreyi, the causative agent of chancroid is a fastidious organism difficult to culture and identify. Consequently, culture is an insensitive method for diagnosis. The polymerase chain reaction (PCR) offers a sensitive and specific nonculture method for the detection of bacterial pathogens. STUDY DESIGN: A polymerase chain reaction (PCR) assay was developed to detect the presence of Haemophilus ducreyi. A pair of primers was selected from sequences of an anonymous fragment of DNA cloned from H. ducreyi. The primers were tested in amplification reactions with both purified DNA and lysed organisms for their ability to detect H. ducreyi, and with DNA from a variety of different bacteria for their specificity. The utility of the primers for the detection of H. ducreyi in samples taken from genital ulcers was also tested and compared with culture. RESULTS: PCR was positive for 62% of the specimens that were culture-positive, however, PCR was also positive for 49% of the culture-negative specimens. Comparison of specimens that were dark field positive for T. pallidum and PCR-positive with those that were culture-positive for herpes simplex virus and PCR positive suggested that PCR was giving true and not random positive results. Additional studies demonstrated that the failure of PCR to detect H. ducreyi in all of the culture-positive specimens probably resulted from inhibitors of the Taq DNA polymerase that were present in the nucleic acids extracted from the clinical specimen. CONCLUSION: PCR should be a useful method for the detection of H. ducreyi in genital lesions, especially where culture sensitivity is poor. However, the presence of unidentified Taq polymerase inhibitors in some ulcers specimens require the development of improved methods for specimen handling.

Chancroid↗
PubMedDate not supplied

Multicenter trial of single-dose azithromycin vs. ceftriaxone in the treatment of uncomplicated gonorrhea. Azithromycin Gonorrhea Study Group.

BACKGROUND AND OBJECTIVES: Azithromycin is a new, long-acting azalide antibiotic that is active against Neisseria gonorrhoeae. A single oral dose of 1.0 g is effective against uncomplicated genital infection with Chlamydia trachomatis. GOAL OF THIS STUDY: To compare the efficacy and tolerance of single-dose treatment of uncomplicated gonorrhea with azithromycin, 2.0 g orally, and ceftriaxone, 250 mg intramuscularly. STUDY DESIGN: Seven hundred twenty-four men and women with presumptive, uncomplicated gonorrhea were treated with azithromycin 2.0 g orally or ceftriaxone 250 mg intramuscularly in a 2:1 ratio in a multicenter, open, randomized control trial in 10 public sexually transmitted disease clinics in the United States. Patients were followed up in 5 to 9 days and, for a subset of patients, 12 to 18 days after treatment. The main outcome measures were the isolation of N. gonorrhoeae and C. trachomatis and patient-reported side effects. RESULTS: Among infected patients who returned for follow-up, N. gonorrhoeae was eradicated from all anatomic sites in 370 of 374 (98.9%; 95% confidence interval [95%CI] 97.9%-100%) treated with azithromycin and 171 of 175 (97.7%; 95%CI 95.5%-99.9%) given ceftriaxone. Treatment with either drug was effective in all 73 patients infected with beta-lactamase-producing N. gonorrhoeae. Chlamydial infection was eradicated in all 17 patients given azithromycin who returned and were recultured at follow-up and in two of seven patients given ceftriaxone (P < 0.001). Gastrointestinal side effects occurred in 35.3% (95%CI 30.7%-39.8%) of patients given azithromycin; of those with symptoms, these were moderate in 10.1% and severe in 2.9%. CONCLUSIONS: Azithromycin 2.0 g and ceftriaxone 250 mg are equally effective in the treatment of uncomplicated gonorrhea. Azithromycin was associated with a relatively high frequency of gastrointestinal side effects and is expensive, but it has the advantages of oral administration and efficacy against concomitant chlamydial infection.

Administration, Oral↗
PubMedDate not supplied

Incision and drainage versus aspiration of fluctuant buboes in the emergency department during an epidemic of chancroid.

GOAL OF THIS STUDY: To compare outcomes of incision and drainage with packing to needle aspiration of purulent buboes in patients with presumed chancroid. The safety and efficacy of incision and drainage were compared with that of needle aspiration. STUDY DESIGN AND METHODS: The study was a prospective randomized, nonblinded clinical trial carried out from April 1992, to January 1994 in an inner city emergency department. A consecutive sample of 27 adults with fluctuant inguinal buboes presumed or proven to be chancroid or lymphogranuloma venereum were eligible for inclusion. Patients were excluded if they were believed to have buboes secondary to disease other than chancroid. After informed consent was obtained, patients had buboes drained by needle aspiration or by incision and drainage with packing according to a random numbers table. RESULTS: Twenty-seven patients were included in the study (22 men and 5 women), with 12 randomized to incision and drainage and 15 to aspiration. The mean age was 35.7 +/- 13 years. Genital ulcer or bubo pus cultures for Haemophilus ducreyi were positive in seven patients, negative in 15 patients, and not done in five patients. Follow-up was obtained for 23 (85%) patients, 11 of whom had incision and drainage and 12 of whom had aspirations. No adverse effects were reported in either group. CONCLUSION: Incision and drainage is an effective method for treating fluctuant buboes and may be preferable to traditional needle aspiration considering the frequency of required re-aspirations in the study patients. Limitations of this study include lack of complete laboratory testing and lack of follow-up of all patients.

Adult↗
PubMedDate not supplied

Toxic and tumorigenic effects of asbestos on tracheal mucosa.

The purpose of the studies was to examine the acute, chronic, and neoplastic effects of asbestos on mucosa of conducting airways. Heterotopic tracheal grafts were used as the experimental model. In the system employed, the test substance was introduced into the airway lumen and kept in intimate contact with the respiratory tract mucosa for weeks or months. UICC chrysotile A and crocidolite asbestos caused marked acute changes of the tracheal mucosa: epithelial hyperplasia, hypersecretion of mucus, and submucosal inflammation. With chrysotile, the hypersecretory state and goblet cell hyperplasia persisted for many months, resulting in a marked distension of the tracheal grafts. Other manifestations of chronic irritation were focal squamous metaplasias, epithelial erosions, and connective tissue changes involving the tracheal submucosa and adventitia as well as the host subcutaneous tissues. The connective tissue changes were characterized by formation of granulomas, often with necrotic centers. In a 29-month tumor-induction study carried out with chrysotile A, the total tumor incidence in 40 tracheal grafts was 40 percent; this included 2 squamous cell carcinomas (5%)(, and 14 sarcomas (35%) as compared with no carcinomas and 6 sarcomas (12%) in 49 vehicle-treated controls. Thus our studies show that chrysotile (1) causes chronic irritation of the tracheal mucosa, (2) augments sarcoma development, and (3) is a weakly but definitely carcinogenic agent for the respiratory tract mucosa.

Animals↗
PubMedDate not supplied

Recent changes in the epidemiology of genital ulcer disease in the United States. The crack cocaine connection.

The incidence of syphilis and chancroid began to increase in the United States among heterosexuals in the mid-1980s, with most cases reported among minorities living in Eastern cities and in the South. A number of studies have established a link between increasing syphilis incidence rates and cocaine use, specifically the smoked form of the drug, which is known as "crack." A similar link was hypothesized for chancroid, but supporting data became available only recently. In New Orleans, we showed that Haemophilus ducreyi infection in male patients was strongly associated with crack cocaine use. However, our studies also demonstrated that drug use by the patient actually was a marker for a more important risk factor: sexual exposure to a cocaine-using woman. Thus, although the details of the relationships among crack, sexual behavior, and the size and nature of core transmitter groups are not known, it is clear that crack cocaine abuse is the driving force behind the recent syphilis and chancroid epidemics in the United States. Although it is not possible to predict the effects of these events on human immunodeficiency virus (HIV) transmission, the potential for significant synergism between them exists. New approaches to HIV surveillance should be developed taking this possibility into account. During the last 3 to 4 years, incidence rates of syphilis and chancroid have fallen in the United States, despite continued problems throughout the country with crack cocaine abuse. However, our studies and those of others have shown how difficult it is to recognize chancroid clinically, suggesting that the disease may be grossly underreported.(ABSTRACT TRUNCATED AT 250 WORDS)

Chancroid↗