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Biomedical subjects

K Jackson

Publications and source records attributed to K Jackson.

At least 91 records · Page 5Linked to original sources
PubMed1994

The Homeless Prenatal Program: a model for empowering homeless pregnant women.

The Homeless Prenatal Program (HPP) is one of the first programs in the country to provide comprehensive prenatal services to homeless pregnant women. A formative evaluation was conducted in 1992, indicating that HPP is achieving its program goals of improving birth outcomes and transforming the lives of its clients. Results of the qualitative evaluation are presented, including HPP's service model and approach to empowerment. In this model, empowerment has two central tenets, derived from the special needs of women who are pregnant and homeless: the "mother-child connection," and the principle of "giving back."

Child↗
PubMed1994

Parenting and childrearing attitudes among high school students.

A descriptive study to assess parenting and childrearing attitudes was conducted among 502 high school students in a greater metropolitan area in the Southeast. The Adult-Adolescent Parenting Inventory (Bavolek, 1984) was used to identify students' scores on four constructs associated with abusive parenting: inappropriate parental expectations, lack of empathy toward the child, value of physical punishment, and parent-child role reversal. Several group differences were found by sex, race, grade, and birth order. Ten percent of students scored consistently low and could be targeted for education programs to increase parenting knowledge and skill.

Adolescent↗
PubMed1993

Safety of lumbar puncture in patients with hemophilia.

STUDY OBJECTIVE: To determine the safety of lumbar puncture in patients with hemophilia who are pretreated with clotting factor. DESIGN: Retrospective analysis of medical records between 1980 and 1990. SETTING: Three hospitals, each serving as a regional hemophilia center. PARTICIPANTS: Thirty-three patients with hemophilia A or B who received one or more lumbar puncture. INTERVENTION: All patients received replacement of deficient factor before the lumbar puncture. Serious post-lumbar puncture complications were defined as motor or sensory deficits, incontinence, or documented intraspinal hemorrhage. RESULTS: Thirty-three patients with hemophilia A or B received a total of 52 lumbar punctures during the study period. Thirty of 33 patients (91%) had severe baseline factor deficiency, two (6%) had moderate deficiency, and one (3%) had mild deficiency. There were no serious complications reported as a result of the lumbar puncture. The 95% confidence interval for the risk of a serious complication was 0% to 5.8%. CONCLUSION: With adequate factor replacement, a lumbar puncture can be done safely in patients with hemophilia.

Adolescent↗
PubMed1993

Delayed desensitization of alpha 2-adrenoceptor-mediated platelet aggregation in depressed patients.

After prolonged exposure to epinephrine, platelets are observed to desensitize alpha 2-adrenoceptor-mediated aggregation responses in vitro. Herein, this phenomenon was studied as a possible in vitro model for alpha 2-adrenoceptor dysregulation in depression. Platelet-rich plasmas obtained from 22 unipolar depressed patients and 25 healthy subjects were preincubated with 20 mumol/L of epinephrine for various lengths of time prior to stirring. By comparing the subsequent extents of aggregation, we observed significantly less desensitization at 4, 20, 30, or 60 minutes postepinephrine exposure (p < or = .05) in depressed patients as compared to healthy controls. This blunted desensitization appeared to be due to a delayed onset of desensitization during the first 0.5 to 2 minutes after epinephrine exposure, since thereafter, the monoexponential desensitization rate did not differ in depressed patients, but the extent of desensitization remained less as compared to healthy subjects. The extent of desensitization was correlated (r = -0.48, p = .02) with the density (Bmax) of the alpha 2-adrenoceptor high-affinity state, as detected in undesensitized platelet membranes by p125I-clonidine binding. An elevation was also observed in the density of nonadrenergic p125I-clonidine-binding sites (putative imidazoline I1 sites) in platelet membranes from depressed patients compared to healthy control subjects. Following treatment with desipramines, the patients (n = 15) displayed more normal (nonblunted) extents of desensitization of aggregation, and the Bmax values for the putative I1 sites were at the levels of healthy controls. If similar aberrations exist in neurons of depressed patients, this may explain a dysregulation of the noradrenergic system believed to underlie depression.

Adult↗
PubMed1993

DNA restriction fragment analysis to define an extended cluster of tuberculosis in homeless men and their associates.

A cluster of tuberculosis in men associated with shelters for the homeless in Melbourne, diagnosed between April 1984 and July 1991, was reviewed with respect to the genetic relatedness of the infecting strains. Relatedness was determined by examination of Southern blot analyses of restriction enzyme-digested genomic DNA, using probes for repetitive sequences. From the initial 24 cases selected, isolates were available from 19, and 18 were identical. A total of 571 other Australian and Solomon Islands strains were examined for relatedness to these strains. Nine additional case strains were found to be identical; all were from recent Melbourne residents and at least 7 were epidemiologically related to the original case cluster. The identification of a single infecting strain of Mycobacterium tuberculosis in these 27 cases suggests that reactivation disease in this group may not be as important as infection or reinfection from another case or cases.

Adult↗
PubMed1993

Mycobacteria in stool specimens: the nonvalue of smears for predicting culture results.

A previous recommendation suggests that stool be cultured for mycobacteria only if the smear is positive. We have correlated smear and culture results of 2,176 stool specimens submitted for mycobacterial culture. The sensitivity, specificity, and positive and negative predictive values for smears to predict culture results are 34, 99, 90, and 87%, respectively. We recommend that the stool smear not be used as a screening technique to decide which specimens from at-risk patients should be cultured because it lacks the necessary sensitivity.

AIDS-Related Opportunistic Infections↗
PubMed1993

Epidural clonidine treatment for refractory reflex sympathetic dystrophy.

BACKGROUND: Intraspinally administered alpha 2-adrenergic agonists may relieve pain in sympathetically maintained pain (SMP) syndromes, such as reflex sympathetically dystrophy (RSD), by spinal, peripheral, and central nervous system actions. This study examined analgesic efficacy and side effects of epidurally administered clonidine in patients with severe, refractory RSD. METHODS: Twenty-six patients with severe chronic pain consistent with RSD were studied in a randomized, blinded, placebo-controlled design. Cervical or lumbar epidural catheters were inserted for patients with upper or lower extremity RSD, respectively, and patients received, in random order on three consecutive days, epidural injection of clonidine, 300 or 700 micrograms, or placebo. Pain (by visual analog score (VAS) and McGill Pain Questionnaire), sedation, blood pressure, and heart rate were monitored at specified intervals for 6 h after injection. Patients who responded to clonidine, but not placebo, then entered a trial of open-label, continuous epidural infusion of clonidine (10-50 micrograms/h). RESULTS: Clonidine, but not placebo, caused pain relief, sedation, and decreased blood pressure and heart rate after bolus epidural injection. The smaller clonidine dose (300 micrograms), produced pain relief and decreases in blood pressure and heart rate similar to those of the 700 micrograms dose, but with less sedation. Epidural clonidine was infused for a mean of 43 days in 19 patients at a mean rate of 32 micrograms/h for sustained analgesia. CONCLUSIONS: Transdermal clonidine has been demonstrated to produce analgesia in the area surrounding its application site in patients with SMP. The current study indicates that extensive analgesia may be obtained by epidural administration. Sedation and hypotension may limit bolus epidural clonidine administration for RSD. The role for chronic epidural infusion of clonidine has not yet been established.

Adult↗
PubMed1992

Safety and immunogenicity in volunteers of a recombinant Plasmodium falciparum circumsporozoite protein malaria vaccine produced in Lepidopteran cells.

A recombinant Plasmodium falciparum circumsporozoite (CS) antigen (rPfCSA) was produced in insect cells using a baculovirus expression vector containing the entire CS gene. This near full-length CS antigen was adsorbed onto aluminium phosphate for use as a malaria vaccine. In a study of safety and immunogenicity, 20 volunteers were divided into four groups of five each and inoculated intramuscularly with 10, 100, 500 or 1000 micrograms of vaccine. Primary vaccinations were followed by two booster immunizations at 2 and 6 months. Three volunteers developed prominent local reactions manifested as tenderness, redness and swelling at the injection site following the second or third vaccination. All symptoms resolved spontaneously within 72 h. Postimmunization sera from six of 20 volunteers showed seroconversions as measured by Western blot, using rPfCSA as antigen. However, specific anti-CS protein antibody could not be detected by indirect immunoflourescence against intact sporozoites or by ELISA using rPfCSA or peptide to the repeat region. In addition, 18 of 20 volunteers developed antibody to baculovirus proteins as determined by ELISA and/or Western blot. Antigen-driven replication studies using peripheral blood mononuclear cells from vaccinees failed to detect proliferative responses specific to CS protein. This recombinant CS protein vaccine, as formulated, was minimally immunogenic in humans.

Adult↗
PubMed1992

Identification of a genetically distinct subspecies of Mycobacterium kansasii.

To assess the usefulness of a specific DNA probe for Mycobacterium kansasii, 105 isolates from Australia, Belgium, Japan, South Africa, and Switzerland were collected and analyzed. Twenty of these isolates were probe negative, of which 18 were from Belgium and Switzerland. Analysis of all isolates by Southern blot hybridization indicated a lack of variability among probe-positive isolates, while probe-negative isolates were clearly distinct and showed greater diversity. Sequence analysis of the 250 nucleotides at the 5' end of the 16S rRNA gene revealed that 19 of the 20 probe-negative isolates had a sequence different from that of M. kansasii. A total of five nucleotide differences were present in a cluster consisting of two nucleotide deletions and three nucleotide substitutions. These results suggest the existence of a genetic subspecies of M. kansasii.

Base Sequence↗
PubMed1992

Isolation of a fastidious Mycobacterium species from two AIDS patients.

Two strains of fastidious mycobacteria were isolated from two patients with AIDS and clinical disease suggestive of Mycobacterium avium complex infection. Acid-fast bacilli were isolated from blood and bone marrow of both patients in BACTEC 12B and/or 13A media. The acid-fast bacilli failed to grow on subculture to routine Löwenstein-Jensen medium containing pyruvate and egg yolk agar. After several attempts, the strain from one patient was finally cultured on Middlebrook 7H9 medium with agar, charcoal, and yeast extract 13 months after the initial specimens were received in the laboratory. The second patient's strain was cultured on the same medium 6 weeks postinoculation with fresh BACTEC fluid and 5 months after specimen collection. Routine biochemical and growth tests were performed on these isolates but failed to give definitive identifications. 16S rRNA gene sequencing suggested that the organisms share at least 98.9% homology with M. simiae. Even greater homology (99.86%) was found with the recently described species "M. genavense." Recognition of the fastidious nature of some mycobacteria that infect AIDS patients is important in the treatment of infections in these patients and in understanding the epidemiology of atypical mycobacterial infections. It is suggested that a liquid culture medium such as BACTEC be employed for primary isolation of mycobacteria from AIDS patients and that subculture to the charcoal medium described here be carried out for those organisms that fail to grow on subculture to routine media.

AIDS-Related Opportunistic Infections↗
PubMed1992

Molecular cloning of a highly repeated DNA element from Mycobacterium tuberculosis and its use as an epidemiological tool.

In order to develop a technique for distinguishing between isolates of Mycobacterium tuberculosis, we cloned two hypervariable DNA fragments from NdeII-digested genomic DNA. The cloned DNA fragments of 3.8 and 4.7 kb were found to contain the same repetitive element, which was different from previously characterized repetitive elements. It is present in at least 30 copies per genome and is distributed among mycobacterial species other than those of the tuberculosis complex, including M. kansaii, M. gastri, and M. szulgai. When used as a probe on restriction enzyme-digested DNA, it can distinguish between strains from unrelated cases of tuberculosis while demonstrating identical banding patterns for isolates from epidemiologically related cases.

Bacterial Typing Techniques↗
PubMed1992

Rate of change of end-stage renal disease treatment incidence 1978-1987--has there been selection?

End-stage renal disease (ESRD) treatment rates in the United States have increased steadily since 1973. Decreasing selection against elderly patients with a poor prognostic primary cause of ESRD (i.e., diabetic nephropathy) may partly account for this increase in rates. To test this hypothesis, we calculated log ESRD treatment incidence (ESRDI) rates by four major primary causes of ESRD (diabetic nephropathy (DN), hypertensive nephropathy (HN), glomerulonephritis (GN), and cystic kidney disease (PC); two age groups (old (O), greater than 65 and young (Y), 15 to 44 yr of age) for black and white, male and female, new ESRD patients from 1978 to 1987. As predicted, summary log ESRDI slopes (produced by analysis of covariance) occurred in the following decreasing order, ODN (0.19), OGN = OHN = YDN (0.134). YHN = YPC = YGN (in white patients) = slope not significantly different from 0. Log ESRDI slopes for young black males and females with GN increased significantly between 1978 and 1987, possibly as a result of an increased incidence of GN. In conclusion, decreasing selection may be a factor in the continuing increase in the U.S. ESRD population.

Adolescent↗
PubMed1991

Operative mortality with implantation of the automatic cardioverter-defibrillator.

Operative mortality was studied in 939 consecutive patients undergoing initial implantation of an automatic implantable cardioverter-defibrillator (AICD) at 15 hospitals. Twenty-nine (3.1%) patients died during the first 30 days after surgery. Among patients who survived beyond the first 30 postoperative days, ejection fraction data were available in 219; compared with the mortality group, these survivors had a significantly higher ejection fraction (34 +/- 15 vs 26 +/- 10%, respectively, p less than 0.001), despite similar age, sex, underlying heart disease, type of presenting arrhythmia and prevalence of concomitant surgery. The causes of perioperative death were sudden in 7 (24%), tachyarrhythmic/nonsudden in 5 (17%), cardiac nonarrhythmic in 9 (31%), and noncardiac in 8 (28%). Twenty-four (83%) of the deaths occurred before hospital discharge, and in all 9 instances of in-hospital sudden and tachyarrhythmic/nonsudden death, the initial recorded rhythm was sustained ventricular tachycardia or fibrillation; in 5 (56%) of these 9 patients the AICD had been in a deactivated state since implantation. Other possible contributory factors in the 12 sudden or tachyarrhythmic/nonsudden deaths included acute myocardial ischemia or infarction in 2 (17%), and "device proarrhythmia" in 3 (25%) that were AICD-related in 2 and secondary to an antitachycardia pacemaker in another; defibrillation threshold testing was not performed in 3 patients (1 of whom had terminal ventricular fibrillation). Thus, in this multicenter experience with thoracotomy requiring AICD implantation, operative (30-day) mortality was 3.1% and correlated inversely with left ventricular ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Cohort Studies↗
PubMed1991

Differentiation of Mycobacterium tuberculosis strains by use of a nonradioactive Southern blot hybridization method.

The only means of dividing strains of Mycobacterium tuberculosis is by phage typing. Attempts at developing a convenient method based on differences in chromosomal DNA by detecting restriction fragment length polymorphisms (RFLP) have had limited success. This report describes the development of a nonradioactive RFLP technique that differs from most methods by using enzymes that have four base recognition sites rather than six. The restriction enzymes AluI, DdeI, HinfI, NdeII, RsaI, and TaqI were used to digest genomic DNA, and high-molecular-weight fragments were visualized after Southern blotting with digoxigenin-labeled M. tuberculosis DNA. Digestion with AluI resulted in different banding patterns among all eight clinical isolates of M. tuberculosis and three type strains from the tuberculosis complex. NdeII distinguished all but two strains, while HinfI and RsaI were unable to distinguish two pairs of strains. Digestion with the enzymes DdeI and TaqI failed to result in clearly discernible bands. These preliminary results suggest that this method provides a fine differentiation of M. tuberculosis strains and may be useful as an epidemiologic tool.

Blotting, Southern↗