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Biomedical subjects

R Shaffer

Publications and source records attributed to R Shaffer.

At least 19 recordsLinked to original sources
PubMed2005

Prevalence and associations of vitamin D deficiency in foreign-born persons with tuberculosis in London.

OBJECTIVES: The incidence of tuberculosis (TB) is high amongst foreign-born persons resident in developed countries. Vitamin D is important in the host defence against TB in vitro and deficiency may be an acquired risk factor for this disease. We aimed to determine the incidence and associations of vitamin D deficiency in TB patients diagnosed at an infectious diseases unit in London, UK. METHODS: Case-note analysis of 210 unselected patients diagnosed with TB who had plasma vitamin D (25(OH)D3) levels routinely measured. Prevalence of 25(OH)D3 deficiency and its relationship to ethnic origin, religion, site of TB, sex, age, duration in the UK, month of 25(OH)D3 estimation and TB diagnosis were determined. RESULTS: Of 210 patients 76% were 25(OH)D3 deficient and 56% had undetectable levels. 70/82 Indian, 24/28 East African Asian, 29/34 Somali, 14/19 Pakistani and Afghani, 16/22 Sri Lankan and 2/6 other African patients were deficient (with 58, 17, 23, 9, 6 and 1 having undetectable levels, respectively). Only 0/6 white Europeans and 1/8 Chinese/South East Asians had low plasma 25(OH)D3 levels. Muslims, Hindus and Sikhs all had equivalent rates of deficiency though Hindus were more likely to have undetectable levels (odds ratio 1.87, 95% CI 1.27-2.76). There was no significant association between 25(OH)D3 level and site of TB or duration of residence in the UK. There was no apparent seasonal variation in either TB diagnosis or 25(OH)D3 level. CONCLUSIONS: 25(OH)D3 deficiency commonly associates with TB among all ethnic groups apart from white Europeans, and Chinese/South East Asians. Our data support a lack of sunlight exposure and potentially a vegetarian diet as contributors to this deficiency.

Case-Control Studies↗
PubMed2001

Chlamydial infection and unplanned pregnancy in women with ready access to health care.

OBJECTIVE: To apply urine-based ligase chain reaction for Chlamydia trachomatis (C. trachomatis) and Neisseria gonorrhoeae (N. gonorrhoeae) detection and standard urine-based pregnancy testing for Navy-enlisted women, and to compare the prevalence and epidemiologic correlates of these adverse reproductive outcomes. METHODS: Participants were surveyed and urine was collected for pregnancy testing using standard laboratory methods and detection of C. trachomatis and N. gonorrhoeae infection by ligase chain reaction. Self-administered surveys facilitated collection of demographics, sexual behavior, including contraceptive use, sexual partners, sexually transmitted disease, and pregnancy history. RESULTS: Among 299 of 314 participants, the prevalence of chlamydial infection was 4.7% and of pregnancy was 9.7%, with 48.3% of the pregnancies unplanned. Chlamydia trachomatis infection was univariately associated with having a new sex partner within the last 6 months, more sexual partners, single marital status, condom use, drinking until passing out or vomiting in the past 30 days (alcohol misuse), and current pregnancy. Unplanned pregnancy was univariately associated with young age, single marital status, inconsistent condom use, having a new sex partner within the last 6 months, and more recent sexual partners. Among the pregnant women, four (13.8%) were infected with C. trachomatis. CONCLUSION: The high rates of chlamydial infection and unplanned pregnancy found in this population of employed young women with ready access to health care and health education underscore the challenge of enhancing reproductive health via compliance with effective contraceptive and sexually transmitted disease prevention methods. This is a challenge that remains unmet.

Adolescent↗
PubMed2000

Military training-related injuries: surveillance, research, and prevention.

BACKGROUND: Musculoskeletal physical training-related injuries are a major problem in military populations. Injuries are important in terms of loss of time from work and training and decreased military readiness. The implications of these injuries in terms of patient morbidity, attrition rates, and training costs for military personnel are staggering. This article reviews: (1) pertinent epidemiologic literature on musculoskeletal injury rates; (2) injury type and location; and (3) risk factors for military populations. Suggestions for injury surveillance and prevention are also offered. METHODS: Existing military and civilian epidemiologic studies were used to estimate and compare the size of the injury problem, identify risk factors, and test preventive measures. Most of the military research data obtained was from Marine and Army recruits, Army Infantry soldiers, and Naval Special Warfare candidates. Additional studies conducted in operational forces provided documentation of the injury problem in these populations as well. RESULTS: Injury rates during military training are high, ranging from 6 to 12 per 100 male recruits per month during basic training to as high as 30 per 100 per month for Naval Special Warfare training. Data collected show a wide variation in injury rates that are dependent largely on the following risk factors: low levels of current physical fitness, low levels of previous occupational and leisure time physical activity, previous injury history, high running mileage, high amount of weekly exercise, smoking, age, and biomechanical factors. (Data are contradictory with respect to age.) CONCLUSION: Considering the magnitude of training injuries in military populations, there is a substantial amount of work that remains to be performed, especially in the areas of surveillance, prevention, and treatment. Modifiable risk factors have been identified suggesting that overuse and other training injuries could be decreased with proper interventions. Outpatient surveillance systems are available to capture musculoskeletal injury data but need to be refined. Given the size of the problem, a systematic process of prevention should be initiated starting with routine surveillance to identify high-risk populations for the purpose of prioritizing research and prevention. Properly planned interventions should then be implemented with the expectation of dramatically reduced lost work/training time, attrition, and medical costs, while increasing military readiness.

Adult↗
PubMed2000

Stress fractures of the pelvis in female navy recruits: an analysis of possible mechanisms of injury.

The purpose of our study was to investigate possible risk factors and mechanisms for the development of pelvic stress fractures in female Navy recruits. We used a case-control retrospective study of female Navy recruits undergoing basic military training. We compared anthropometric and activity data between recruits with pelvic stress fractures (N = 25) and female recruits who completed training without injury (N = 61). Recruits developing pelvic stress fractures were significantly (p < 0.05) shorter and lighter and were more frequently Asian or Hispanic than recruits without stress fractures. In addition, recruits with pelvic stress fractures reported marching in the back of their training division, were road guards, and felt that their stride was too long during training activities more often than recruits without injury. Self-reported fitness, activities before recruit training, or a history of amenorrhea was not found to be associated with the development of a pelvic stress fracture in our population.

Adolescent↗
PubMed1997

Preoperative ICU tours: are they helpful?

BACKGROUND: Although preoperative education decreases the anxiety of patients and family members, the usefulness of a preoperative tour of the ICU has not been studied. In this study, the effect of an ICU tour on the anxiety levels of patients (n = 92) and family members (n = 91) before and after cardiac surgery was examined. METHODS: Using a pretest-posttest quasi-experimental design, patients and family members were assigned to a control group, which received preoperative teaching only (patients, n = 48; family members, n = 48), or to an experimental group, which received preoperative teaching with an ICU tour (patients, n = 44; family members, n = 43). Patients and family members completed two measures of anxiety, the State Trait Anxiety Inventory and a visual analog scale, before and after the intervention. After their first postoperative visit, family members completed the measures again. Repeated measures analysis of variance was used to compare anxiety levels after the intervention. In addition, patients completed the Patient Perception of the ICU Tour Questionnaire after transfer from the ICU. RESULTS: Although patients and family members had a decrease in anxiety after cardia surgery teaching, the decrease was not due to an ICU tour. However, the majority of patients who toured the ICU perceived the tour as beneficial and recommended a tour for future patients. CONCLUSIONS: ICU tours are included in many cardiac surgery educational programs. The majority of patients in this study perceived a benefit or a future benefit from an ICU tour, even though the tour did not significantly reduce the anxiety of the patients or family members.

Adult↗
PubMed1991

On-line databases of human chromosome anomalies and variants.

Gradual refinements in chromosome technology over the years have enabled biologists to study the chromosomes at the molecular level. An account of the development of a computerized technique for cataloguing all structural and numerical aberrations in human chromosomes and setting up of registries of abnormal human karyotypes for delineation of karyotype-phenotype relationship for future use has been emphasized in the present paper.

Chromosome Aberrations↗
PubMed1987

Vaccinia virus encapsidates a novel topoisomerase with the properties of a eucaryotic type I enzyme.

A DNA topoisomerase has been purified from vaccinia virus cores. The native enzyme is composed of a single subunit of 32,000 daltons. The enzyme relaxes both positively and negatively supercoiled DNA in the absence of an energy cofactor. Enzymatic activity is stimulated by magnesium ions and inhibited by ATP, and during relaxation the topoisomerase changes the linking number of the DNA substrate by steps of one. Trapping of the covalent DNA-enzyme intermediate has been achieved, and analysis of the cleavage of duplex DNA by the enzyme reveals that it makes a single-strand break and forms a covalent bond through the 3'-end of the broken strand. Enzymatic activity and formation of the trapped intermediate are inhibited by the drugs novobiocin, coumermycin A1, and berenil. The virally encapsidated enzyme has novel properties but most closely resembles a eucaryotic type I topoisomerase.

Adenosine Triphosphate↗
PubMed1986

[Left ventricular regional function in patients with dilated cardiomyopathy (computerized echocardiographic data)].

Computerized echography was used to assess left-ventricular dysfunction in 40 patients with dilatation cardiomyopathy (DCM). The so-called "floating" system was shown to be the most acceptable model for the correction of DCM-associated superposition. An original system was used for segment division by two- and four-chamber projections. Total left-ventricular hypokinesia and a significant reduction of the total ejection fraction (32.5 +/- 1.9%) were demonstrated.

Adult↗
PubMed1984

Acyloxyamines as prodrugs of anti-inflammatory carboxylic acids for improved delivery through skin.

An N,N-dialkylhydroxylamine derivative of indomethacin has been synthesized. It has been shown to improve the delivery of indomethacin through mouse skin (compared to indomethacin itself) by a factor of two, to be more effective than indomethacin in inhibiting thermal inflammation (two to three times) in animal models, but to be only as effective as indomethacin in inhibiting UV-B radiation erythema in human volunteers.

Administration, Topical↗
PubMed1983

Simultaneous analysis of 1-beta-D-arabinofuranosylcytosine, 1-beta-D-arabinofuranosyluracil and sodium salicylate in biological samples by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic column switching system is described for the rapid and complete separation of 1-beta-D-arabinofuranosylcytosine (Ara-C), 1-beta-D-arabinofuranosyluracil (Ara-U) and sodium salicylate using an internal standard of sodium cefmetazole. The system is highly selective and separates these compounds from interfering compounds commonly in biological matrices. The system was tested by following the pharmacokinetics of Ara-C after rectal administration in the presence of sodium salicylate which is an aid to drug absorption. The chromatographic system is also suitable for monitoring levels of Ara-C and its metabolite Ara-U after intravenous administration of Ara-C.

Animals↗