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Biomedical subjects

F M LaForce

Publications and source records attributed to F M LaForce.

At least 37 records · Page 2Linked to original sources
PubMed1992

Pneumococcal bacteremia in Monroe County, New York.

OBJECTIVES: Knowledge of the epidemiology of pneumococcal disease is critical for public health planning, evaluation of preventive strategies, and development of immunization recommendations. METHODS: We studied the incidence and case-fatality rates of pneumococcal bacteremia as a proxy for pneumococcal disease in Monroe County, New York, from 1985 through 1989 by reviewing the laboratory and clinical care records of all cases occurring among residents. RESULTS: There were 671 cases identified, for an overall yearly rate of 18.8 per 100,000. The rates were highest in the very young, in the very old, and in non-White populations. Age-specific rates were consistently higher in Blacks than in Whites. Predisposing medical conditions were present in 61% of cases. Case-fatality rates were 15% overall, 27% in those with predisposing medical conditions, and approximately 30% in Blacks older than 55 years and Whites older than 65 years. CONCLUSIONS: This study documents the incidence of and mortality from pneumococcal bacteremia. It supports previous observations that Black populations have an increased risk of invasive pneumococcal infection and suggests that immunization should be considered for Blacks older than 55 years.

Black or African American↗
PubMed1992

Evaluation of respiratory problems.

Respiratory problems are common in international travelers. Most are self-limited and do not result in significant morbidity. Those that are severe enough to result in fever and an abnormal chest roentgenogram may pose diagnostic difficulties. The familiar bacterial respiratory pathogens found worldwide are the most common causes of this syndrome, but less familiar entities also need to be considered. A careful evaluation, including a thorough travel history, should yield the diagnosis.

Global Health↗
PubMed1991

Achievable influenza immunization rates in the elderly.

We sought to determine achievable rates of influenza immunization in a large internal medicine practice in which free vaccination was vigorously promoted. A list of 1,230 patients over 65 years of age constituted the target population. Seven hundred ninety patients (64%) were immunized in the office from September to December 1989. In early 1990, questionnaires were sent to 67 patients who had refused vaccination and to an equal number of age- and sex-matched controls who had either accepted the vaccine or whose immunization status was unknown. Seventy-four percent returned the questionnaires. Of the 67 unimmunized patients, 39 (53%) reported that they might be persuaded to accept immunization, whereas 22 (33%) said that nothing could convince them to be immunized. When we added persons who might accept influenza vaccine and persons who had received the vaccine in public clinics to the total number of patients immunized in the office setting, we reached a total of 1,059 patients (86.1% of the total), which we would propose as the maximal achievable immunization rate in this setting.

Aged↗
PubMed1990

Lactoferrin and transferrin damage of the gram-negative outer membrane is modulated by Ca2+ and Mg2+.

Lactoferrin and transferrin have antimicrobial activity against selected Gram-negative bacteria, but the mechanism of action has not been defined. We studied the ability of lactoferrin and transferrin to damage the Gram-negative outer membrane. Lipopolysaccharide release by the proteins could be blocked by concurrent addition of Ca2+ and Mg2+. Addition of Ca2+ also blocked the ability of lactoferrin to increase the susceptibility of Escherichia coli to rifampicin. Transferrin, but not lactoferrin, increased susceptibility of Gram-negative bacteria to deoxycholate, with reversal of sensitivity occurring with exposure to Ca2+ or Mg2+. In transmission electron microscopy studies polymyxin B caused finger-like membrane projections, but no morphological alterations were seen in cells exposed to EDTA, lactoferrin or transferrin. These data provide further evidence that lactoferrin and transferrin act as membrane-active agents with the effects modulated by Ca2+ and Mg2+.

Calcium↗
PubMed1990

Poliomyelitis vaccines. Success and controversy.

The conquest of poliomyelitis by killed and live poliomyelitis vaccines is arguably the most successful American public health project. In 1950, 20,000 cases of paralytic poliomyelitis were reported in the United States, whereas in recent years, fewer than 10 cases were reported. These few cases were largely associated with oral vaccine and despite their small number have led to a reconsideration of killed vaccine as a public health measure in the United States.

Global Health↗
PubMed1989

The periodic physical examination in asymptomatic adults.

The components of the periodic physical examination have been evaluated according to contemporary epidemiologic standards. For the asymptomatic, nonpregnant adult of any age, no evidence supports the need for a complete physical examination as traditionally defined. The efficacy for three screening procedures has been established: Blood pressure should be measured at least every 2 years; women more than 40 years of age should have a breast examination done by a physician annually; and sexually active women should have a pelvic examination and a Papanicolaou test at least every 3 years after two initial negative tests have been obtained 1 year apart. Because of the prevalence and morbidity of specific diseases, and the sensitivity and specificity of screening tests, several other maneuvers are recommended for screening asymptomatic adults, although the optimal frequency has not been determined experimentally. Weight should be measured every 4 years. Visual acuity should be tested annually in adults older than 60 years of age. To identify patients at high risk for melanoma, a complete skin examination should be done once. Hearing should be tested by audioscope annually in adults older than 60 years of age. Physicians should encourage patients to have annual dental visits. To identify valvular abnormalities requiring antibiotic prophylaxis, cardiac auscultation should be done at least twice in an adult. Men older than 60 years of age should have a yearly examination of the abdomen for the presence of aortic aneurysm. Although the other components of the complete physical examination may be important in establishing and maintaining the physician-patient relationship, they have not been shown to be effective screening maneuvers for asymptomatic disease.

Adult↗
PubMed1989

Systemic antimicrobial therapy of nosocomial pneumonia: monotherapy versus combination therapy.

The treatment of nosocomial pneumonia is difficult because of the absence of a precise microbial etiology in a sizable fraction of cases and the severity of predisposing conditions in patients who develop these infections. Staphylococcus aureus and aerobic gram-negative rods continue to be the most common isolates in these infections. Therapy of nosocomial pneumonia is often empiric, with initial antimicrobial therapy based upon local experience and sensitivity patterns, immune competence of the patient and disease severity. Combination therapy with an aminoglycoside and a beta-lactam has long been the cornerstone of therapy, and clinical success has been correlated with peak serum bactericidal levels of 1:8 in non-granulocytopenic patients and peak gentamicin and tobramycin levels greater than 8 micrograms/ml. The introduction of new broad-spectrum antibiotics, such as monobactams, third-generation cephalosporins and imipenem, has introduced the possibility of monotherapy for the treatment of nosocomial pneumonia. In general, monotherapy has proven to be a useful alternative to combination therapy, with success rates ranging from 77 to 96%. Development of resistance during therapy, particularly by Pseudomonas, Enterobacter and Serratia spp., remains an unresolved problem.

Agranulocytosis↗
PubMed1989

Pneumococcal vaccine.

Pneumococcal infections are common and serious infections, and their control is an important public health priority. A multivalent pneumococcal vaccine was introduced several years ago, but there is still controversy about its effectiveness in United States populations. One randomized controlled study in high-risk veterans did not demonstrate efficacy. The study has been criticized because the case definitions used for pneumococcal infection had uncertain specificity. Two large case control studies done in Pennsylvania and Connecticut hospitals have compared vaccination rates in patients with pneumococcal bacteremia with controls matched for disease severity and age. Bacteremic immunosuppressed patients who were unlikely to have responded to pneumococcal vaccine were excluded. These studies showed vaccine efficacy rates in the 60% to 70% range as did a prospective randomized controlled French trial that used episodes of pneumonia as an end point. Pneumococcal vaccine is effective when given to patients likely to respond immunologically and who are at increased risk from pneumococcal infection.

Administration, Cutaneous↗
PubMed1988

Damage of the outer membrane of enteric gram-negative bacteria by lactoferrin and transferrin.

Many studies have shown that lactoferrin and transferrin have antimicrobial activity against gram-negative bacteria, but a mechanism of action has not been defined. We hypothesized that the iron-binding proteins could affect the gram-negative outer membrane in a manner similar to that of the chelator EDTA. The ability of lactoferrin and transferrin to release radiolabeled lipopolysaccharide (LPS) from a UDP-galactose epimerase-deficient Escherichia coli mutant and from wild-type Salmonella typhimurium strains was tested. Initial studies in barbital-acetate buffer showed that EDTA and lactoferrin cause significant release of LPS from all three strains. Further studies found that LPS release was blocked by iron saturation of lactoferrin, occurred between pH 6 and 7.5, was comparable for bacterial concentrations from 10(4) to 10(7) CFU/ml, and increased with increasing lactoferrin concentrations. Studies using Hanks balanced salt solution lacking calcium and magnesium showed that transferrin also could cause LPS release. Additionally, both lactoferrin and transferrin increased the antibacterial effect of a subinhibitory concentration of rifampin, a drug excluded by the bacterial outer membrane. This work demonstrates that these iron-binding proteins damage the gram-negative outer membrane and alter bacterial outer membrane permeability.

Cell Division↗
PubMed1988

A radiolabel ratio method for measuring pulmonary clearance of intratracheal bacterial challenges.

Calculation of bacterial clearance is a fundamental step in any study of in situ lung antibacterial defenses. A method is described whereby about 85% of a radiolabeled bacterial inoculum was consistently introduced into the bronchopulmonary tree of a mouse by the intratracheal route. Mice were then killed 1 and 4 hours later; their lungs were removed aseptically and homogenized, and viable bacteria and radiolabel counts were determined. Radiolabel counts fell slowly, and more than 80% of the original radiolabel was still present in homogenized lung samples from animals sacrificed 4 hours after challenge. Bacteria/isotope ratios for the bacterial inoculum and homogenized lung samples from animals sacrificed immediately after challenge were very similar. Bacterial clearance values were the same whether computed from bacterial counts alone or according to a radiolabel ratio method whereby the change in the bacteria/isotope ratio in ground lung aliquots was divided by a similar ratio from bacteria used to inoculate animals. Some contamination resulted from oral streptococci being swept into the bronchopulmonary free during the aspiration process. This contamination was not a problem when penicillin was incorporated into the agar and penicillin-resistant strains were used for the bacterial challenges.

Animals↗
PubMed1987

Preventive strategies in sexually transmitted diseases for the primary care physician. US Preventive Services Task Force.

This study provides the background recommendations of the US Preventive Services Task Force for interventions by primary care physicians to prevent sexually transmitted diseases. Rationale for and data supporting use of barrier methods, epidemiologic treatment, contact tracing, patient education, prophylactic antibiotics, and disease reporting are discussed. Specific recommendations include those for gonorrhea, syphilis, human immunodeficiency virus infection, enteric infections, human papillomavirus infection, herpes simplex virus infection, and Chlamydia trachomatis infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Inefficacy of pneumococcal vaccine in a high-risk population.

Use of pneumococcal vaccine remains controversial. To further study this question, 89 patients hospitalized at the Denver Veterans Administration Medical Center with pneumococcal bacteremia were chosen as the case group for a case-control study. The control group was made up of patients matched on the basis of age, date of admission, and comorbid conditions. Vaccination status in the bacteremic patients and control patients was determined, as were pneumococcal serotypes among the bacteremic patients. If the vaccine were protective, vaccination rates should be higher among the control patients, and serotype distribution should be different in vaccinated and nonvaccinated bacteremic patients. There were no differences between vaccination rates among bacteremic patients (29 percent) and control patients (24 percent). Furthermore, 65 percent of the blood isolates from nonvaccinated bacteremic patients were serotypes included in the vaccine, as compared with 69 percent of the isolates in vaccinated bacteremic patients. Pneumococcal vaccine did not appear to be protective in this high-risk population.

Age Factors↗
PubMed1987

Release of lactoferrin by polymorphonuclear leukocytes after aerosol challenge with Escherichia coli.

Mice with cyclophosphamide-induced granulocytopenia were challenged with aerosolized Escherichia coli, their lungs were lavaged at 1 and 4 h, and total cell counts, differential counts, and levels of lactoferrin, transferrin, and albumin were measured in the lung lavage fluid. Lung lavage fluid from cyclophosphamide-treated mice had few neutrophils and no increase in lactoferrin levels, whereas control mice had significant increases in both. Transferrin levels did not change in either group. Neutrophils are the source of increased lactoferrin levels in lung lavage fluid after aerosol challenge.

Aerosols↗