Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or...
Reexamination Certificate
1999-05-05
2001-01-16
Le, Long V. (Department: 1641)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
C435S004000, C435S007100, C435S007920, C435S962000, C435S970000, C435S973000, C436S063000, C436S802000, C436S805000, C436S811000, C514S012200
Reexamination Certificate
active
06174664
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of screening for inflammatory diseases in a patient. More particularly, this invention concerns the method of screening a patient for the presence of inflammatory diseases such as an intraamniotic infection, bacterial meningitis and the sexually transmitted diseases; gonorrhea, chlamydia and trichomoniasis, by utilizing neutrophil defensins and lactoferrin, found in a bodily fluid, a tissue or a combination thereof, to give an indication of whether the patient is at risk of suffering from one or more such inflammatory diseases.
2. Description of Related Art
The methods of disease detection may be divided into two general types: diagnosis and screening. Diagnosis is the method whereby a physician determines the nature of a disease based upon the patient's signs and symptoms. Screening is the method of suggesting the presence, or the absence, of a particular disease, or class of diseases, in a patient. When a screening test indicates that a patient does not have a disease, in many cases the need for further diagnostic testing has been eliminated. Used in this manner, screening saves money for patients, health insurance companies and government health programs by precluding the unwarranted diagnostic testing of people shown not to suffer from the disease or class of diseases. To be effective in reducing unnecessary diagnostic testing, however, a screening method must be widely used. In order that a screening method is widely used, the screening test should be relatively accurate, quick, and economical to use.
In addition, screening provides a way for patients to avoid the cost and discomfort associated with the more invasive procedures often necessary to collect the samples required for diagnostic testing. The following are some of the conventional methods used for screening and diagnosing inflammatory conditions such as an intraamniotic infection, bacterial meningitis, and the sexually transmitted diseases; gonorrhea, chlamydia and trichomoniasis.
a. Intraamniotic Infections
An intraamniotic infection is an infection of the amnion or of the amniotic fluid by any pathogen. It is thought to be a significant cause of idiopathic preterm labor, which results in preterm deliveries. The typical screening procedure for an intraamniotic infection involves the physician empirically identifying women in preterm labor. Unfortunately, the majority of women with preterm labor do not have overt signs or symptoms of intraamniotic infection, such as fever, increased heart rate and abdominal tenderness between contractions.
The standard test for diagnosing an intraamniotic infection involves the physician obtaining an amniotic fluid sample from the patient via amniocentesis. This is followed by growth of a culture from the extracted fluid. Diagnosis is both costly and time consuming, because a physician must perform the amniocentesis procedure to procure the necessary sample and skilled laboratory personnel are needed to grow and analyze the culture. Growth of the specimen requires at least 24 hours, which significantly delays treatment. Further, diagnosis is often negative in cases where there is significant placental infection or inflammation. Also, the procedure itself can present a risk to the fetus, and discomfort to the mother. Therefore, many clinicians diagnose intraamniotic infections solely based on the inability to stop labor with tocolytics. Recent evidence linking infection to cerebral palsy suggests that this practice may potentially be harmful. Clearly, more rapid means of identifying patients with intraamniotic infection are needed.
b. Bacterial Meningitis
Bacterial meningitis afflicts approximately 10,000 people annually. The typical screening method for bacterial meningitis involves empirical observation by the physician of the presence of the following symptoms in children: fever with temperature, instability, 35 irritability or lethargy, refusal to feed, vomiting and diarrhea and respiratory distress. In adults, the physician looks for: fever, headache, meningismus or irritation of the lining of the brain and altered mental status. Complications of bacterial meningitis can include death and neurologic sequalae in approximately 10-20% of patients. Figures are higher in immunosuppressed patients such as newborn babies. Fortunately, early diagnosis and treatment will reduce these complications.
Bacterial meningitis is typically diagnosed by first obtaining a sample of cerebrospinal fluid (CSF) from the patient by means of a lumbar puncture. This sample is then cultured and stained for Gram positive bacteria. Also, measurements of white blood cells, glucose and protein in the cerebrospinal fluid can be made. Deviations in these parameters from normal levels can be used by the physician to diagnose bacterial meningitis. A CSF white blood cell count greater than 1000/&mgr;L, a CSF glucose level less than 30 mg/dL and a CSF protein level greater than 100 mg/dL, can be used alone or in combination to diagnose bacterial meningitis in a patient. The major drawback to using these tests individually to diagnose bacterial meningitis lies in their low sensitivity. While positive Gram stains have an eighty-four percent (84%) sensitivity, white blood cell counts have a sensitivity of only fifty-three percent (53%), and glucose levels have only a fifty-eight percent (58%) sensitivity. Protein levels have a sensitivity of ninety percent (90%). Therefore, these tests are typically utilized in combination, with an abnormality in any one test being used to predict bacterial meningitis. If all four tests are used in this manner, they can result in approximately a ninety-five percent (95%) sensitivity. (See Table 2) Performing all these tests, however, can also result in more expense being borne by the patient because a physician must perform the lumbar puncture and a competent laboratory must conduct the testing. Making a diagnosis in this manner can also result in a longer time being required because the physician may have to await the results from four tests before being certain that there is an abnormality in at least one test.
c. Sexually Transmitted Diseases
The typical screening method for sexually transmitted diseases involves the physician noting the patient complaining of painful or difficult urination, called dysuria, and abnormal discharge. The physician then checks the patient for redness, swelling or sores on or about the genitalia. Additional screening methods include using the leukocyte esterase dipstick or neutrophil quantification on Gram stain or wet smear. Unfortunately, these methods have sensitivities of thirty-three percent (33%) to eighty percent (80%) with specificities of fifty percent (50) to eighty percent (80%) thereby making them less than ideal for routine clinical use.
Another type of screening method for sexually transmitted diseases, employed by the World Health Organization and by some Third World countries, involves the use of an algorithm comprising a series of questions. Because this screening method is based solely on the patient's answers to questions, which may be either inaccurate or untruthful, and not on any physical assessment of the patient by a physician, the degree of error is likely to be quite high. Further, because of the scarcity of resources in Third World countries, no other test is performed in those cases where the answers do not suggest the presence of an infection, thereby neglecting many patients who are infected.
Several diagnostic tests for sexually transmitted diseases are readily available in the United States and other developed nations. The most accurate diagnostic techniques are PCR and LCR, both of which amplify the amount of pathogenic microbial genetic material in a patient specimen to detectable levels. The use of PCR and LCR is limited by the expense involved in having a physician collect a specimen from the patient and the costs for a proficient facility to perform the necessary lab work.
(1) Gonorrhea
Gonorrhea is caused b
Gabel Gailene R.
Le Long V.
Thorp Reed & Armstrong LLP
University of Pittsburgh
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