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Biomedical subjects

S Baker

Publications and source records attributed to S Baker.

At least 109 records · Page 6Linked to original sources
PubMed1995

Depression in substance-dependent delinquents.

OBJECTIVE: Depression often is comorbid with conduct disorder. The purpose of this study is to assess whether, among youths with conduct disorder, those with depression differ in other ways from those without depression. METHOD: Ninety-nine delinquent boys (aged 13 through 19 years) were evaluated with the Diagnostic Interview Schedule for Children and other instruments. All boys had conduct disorder and substance use disorders. RESULTS: Staff-rated and self-rated depression scores correlated significantly. Twenty-one boys had major depression and/or dysthymia. Depressed boys had more substance dependence diagnoses and were more likely to have attention-deficit hyperactivity disorder, posttraumatic stress disorder, and anxiety disorders, compared with the nondepressed boys. Depressed boys tended to develop conduct symptoms earlier than did the nondepressed boys. Depression scores did not change after at least 4 weeks of abstinence, for either depressed or nondepressed boys. CONCLUSIONS: Depressed delinquents have more substance dependence diagnoses, tend to initiate behavioral problems at an earlier age, have increased anxiety and attentional problems, and more trauma effects, than nondepressed delinquents. Depression does not appear to be related to substance intoxication, since it is not alleviated after 4 weeks of abstinence. Such boys may require combined psychiatric and substance treatment.

Adolescent↗
PubMed1995

Elongation activity of poliovirus RNA polymerase derived from Sabin type 1 sequence is not temperature sensitive.

Determinants of attenuation in the Sabin type 1 strain of poliovirus are located in the 5' noncoding region, the capsid coding region and the viral RNA-dependent RNA polymerase (3Dpol) coding region. These mutations also contribute to a temperature sensitive pheno-type of virus replication. We have cloned and expressed the Sabin 1 virus 3Dpol) protein which contains three amino acid differences from the wild-type (Mahoney) sequence, as well as a wild- type polymerase containing only a single Sabin amino acid substitution at nt 6203. These enzymes have been examined and compared for temperature sensitive polymerase activity. Wild-type and mutated polymerases demonstrated identical specific activities at 30, 35 and 39 degrees C. All three showed the same kinetics of heat inactivation after pre-incubation at elevated temperatures. Thus the contribution of Sabin 3Dpol sequences to the inability of the virus to grow at elevated temperatures must lie in a function or activity of the enzyme other than RNA polymerization. A likely reaction is the initiation step of RNA chain synthesis.

Cloning, Molecular↗
PubMed1995

Signal-averaged electrocardiography of the sinus and paced P wave in sinus node disease.

The detection of paroxysmal atrial fibrillation (AF) in patients requiring a permanent pacemaker for sinus node disease may influence the choice of both pacemaker and programmed mode. While signal-averaged ECG of the P wave (SAEP) during sinus rhythm may detect patients with paroxysmal AF, the value of SAEP in the presence of sinus node disease is unknown. We therefore evaluated SAEP in patients with sinus node disease during sinus rhythm and atrial pacing. We investigated 10 patients with sinus node disease alone (SND), 10 with sinus node disease and paroxysmal AF (SND-PAF), and 20 normal controls (NC) using a P wave specific, signal-averaging system. In sinus rhythm, duration and energy were greater in SND-PAF than in SND and NC (mean [SEM] duration: 153 [4] msec, 140 [4] msec, and 134 [2] msec, P < 0.001; energy from 20-150 Hz: 76 [18] muV2.sec, 48 [7] muV2.sec, and 36 [3] muV2.sec, P = 0.006). Atrial pacing in SND-PAF produced an 11% prolongation of atrial activation but little further abnormality in P wave characteristics. In SND, atrial pacing caused a 20% prolongation of the P wave and increased P wave energy to a greater extent than in SND-PAF. We conclude that in patients with SND, atrial activation appears similar to normal controls during sinus rhythm but changes significantly on pacing. In patients with SND-PAF, atrial activation is abnormal during sinus rhythm with little further change when the atrium is paced. SAEP may be useful in detecting a predisposition to paroxysmal AF in the presence of sinus node disease and might help optimize pacemaker prescription.

Adult↗
PubMed1995

Cerebral palsy.

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Cerebral Palsy↗
PubMed1995

Patient identification and bystander-initiated actions in acute myocardial ischemia.

From the onset of symptoms of acute myocardial ischemia to initiation of emergency medical services is a delay over which health-care professionals have the least control. Treatment modalities greatly depend upon rapid recognition and early therapy. Patient identification of specific symptoms can be helpful and recognition can be improved by targeted, public educational efforts. Completion of a seamless 9-1-1 system in Florida is necessary as well as instruction in its proper use. Simplified cardiopulmonary resuscitation instruction needs to be given to those persons most likely to be exposed to a sudden cardiac death victim. The physician's office staff should be educated so they can enlighten patients regarding the need for rapid treatment in acute situations. Appropriate utilization of automatic external defibrillators needs to be studied.

Cardiopulmonary Resuscitation↗
PubMed1995

Expression of p53 antigen in inflamed and regenerated mucosa in ulcerative colitis and Crohn's disease.

Physiologic overexpression of p53 protein may occur in the G1 stage of the cell cycle to slow down the cell cycle and allow DNA repair in stressed or injured cells. We questioned whether there is increased expression of p53 protein in acutely inflamed mucosa (AI) and regenerated mucosa (RM) in ulcerative colitis (UC) and Crohn's disease (CD). Formalin-fixed paraffin-embedded sections of resected bowels from eight patients with UC and 20 with CD were reviewed, and blocks were selected having areas defined as follows: AI = two high-power fields (HPFs) at the edge of an ulcer, or one HPF with an inflamed crypt in the center; RM = branched or irregular glands with only mild chronic inflammation. Blocks with normal mucosa were available in 20 cases. One case of CD also had dysplasia, adenoma, and invasive carcinoma. p53 was identified with PAb1801 antibody using a labeled avidin-biotin immunoperoxidase technique. In each defined area, the positive nuclei were counted and expressed as the number of positive nuclei per 10 HPFs. Data were analyzed statistically for comparisons within and between the diseases. In normal mucosa, only rare cells expressed p53 in two cases of CD. The mean frequency of positive nuclei was 2.24/10 HPFs in AI and 0.30/10 HPFs in RM in CD, and 7.63/10 HPFs in AI and 1.14/10 HPFs in RM in UC. Differences between the means for AI and RM were statistically significant in both UC and CD. Although not significant, the frequency of positive staining in both AI and RM was greater in UC as compared with CD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Macrothrombocytosis in cavalier King Charles spaniels.

Low platelet counts (< 150 x 10(9)/litre) have been measured by autoanalyser in cavalier King Charles spaniels with a wide range of diseases. However, the direct examination of blood smears revealed adequate numbers of platelets but many abnormally large platelets and it was not clear whether the large platelets were the result of disease or a breed abnormality. The numbers and diameters of the platelets in a group of clinically normal King Charles spaniels and a group of other breeds were measured by autoanalyser and manually. The automated platelet counts were lower in the King Charles spaniels than in the other breeds (P < 0.01), but the manual counts were similar. The platelet diameter was greater in the cavalier King Charles spaniels (median values 2.5 to 3.75 microns, P < 0.001) than the other breeds (median values 1.25 to 2.5 microns) and had a bimodal distribution with peaks at 1.25 to 2.5 microns and 3.75 to 5 microns. No clinical evidence of platelet dysfunction was detected. These findings indicate that cavalier King Charles spaniels may have large platelets which could lead to the erroneous diagnosis of thrombocytopenia by automated haematological analysis.

Animals↗
PubMed1994

Plasma D-dimer and peritoneal CA-125 levels as predictors of disease status in ovarian carcinoma.

Although serum CA-125 has improved our ability to monitor tumor response in ovarian carcinoma, approximately 50% of patients with normalization of CA-125 have persistent disease at second look laparotomy. Peritoneal CA-125 and plasma D-Dimer levels were studied to determine if their use could increase the sensitivity for persistent ovarian carcinoma in a population of patients with normal physical examinations, radiologic studies, and serum CA-125 values. Plasma D-Dimer levels were obtained prior to second look laparotomy. The results of peritoneal CA-125 and plasma D-Dimer studies were compared to second look laparotomy results. Differences were evaluated with a one-way analysis of variance. Twenty-seven patients were studied. Peritoneal CA-125 was evaluated in 23 patients and ranged from < 6.3-223 U/ml. There was no statistical difference in peritoneal CA-125 levels between patients whose second look laparotomies were negative, or microscopically or macroscopically positive. D-Dimer was elevated in three patients, all of whom had macroscopically positive second look findings. The sensitivity for positive second look findings was only 27%. Minimally elevated plasma D-Dimer levels were specific but not sensitive for persistent disease and peritoneal CA-125 was not predictive of disease status.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1994

Surface 12-Lead Electrocardiographic Findings and Plasma Markers of Thrombin Activity and Generation in Patients with Myocardial Ischemia at Rest.

Background: Myocardial ischemia at rest is typically associated with atherosclerotic coronary artery disease, atherommous plaque rupture, and intracoronary thrombosis. In areas of advanced disease and vascular injury, the extent of thrombus is influenced largely by a delicate balance of procoagulant factors, favoring thrombus initiation, growth, and development, and anticoagulant factors, attempting to limit potentially flow-limiting coronary thrombosis. Thrombin, a 308 amino acid serine pretense, is considered the most patent procoagulant factor in the setting of acute vessel wall injury, playing an essential role in the conversion of fibrinogen to fibrin, accelerating the prothrombinase complex, activating platelets, and stabilizing fibrin polymers. The purpose of this study was to determine the relationship between electrocardiographic abnormalities and markers of thrombin activity and generation among patients with unstable angina and non-Q.wave myocardial infarction. Mehtods and Results: In a study of 36 patients (59.1+/- 11.0 years) with myocardial ischemia at rest participating in the Thrombolysis in Myocardial Ischemia (TIMI) IIIB trial, thrombin activity in plasma, as determined by fibrinopeptide A (FPA), prothrombin fragment 1.2 (F 1.2), and thrombin-antithrombin III complexes (TAT) concentrations, were found to be increased significantly when compared with healthy volunteers (p < 0.004). Thrombin generation was also increased modestly compared with age-matched patients with stable coronary artery disease undergoing elective cardiac catheterization. Given that,he surface 12-lead electrocardiogram (ECG) is frequently abnormal in patients with ischemic chest pain at rest and represents a readily available, first-line diagnostic test for assessing disease activity and treatment response, we investigated whether ECG abnormalities and thrombin activity/generation in plasma were correlated. Twenty-six patients (72%) had ECG changes compatible with myocardial ischemia at the time of study entry, including 18 (50%) with newly inverted T waves (or pseudonormalization), 14 (39%) with reversible ST-segment depression, and 4 (11%) with transient (<30 minutes) ST-segment elevation. Within the predefined ECG groups there were no differences in plasma thrombin activity between patients with and those without confirmed abnormalities. Similarly, there were no differences in either plasma thrombin activity or generation between the predefined ECG groups. Conclusion: Although ECG abnormalities supporting the presence of myocardial ischemia occur commonly in patients with chest pain at rest, they do not correlate closely with markers of thrombin activity and generation in plasma. The diagnostic and prognostic capabilities of these diagnostic tools, considered either alone or together, require further investigation.

Journal Article↗
PubMed1994

Health Belief Model variables as predictors of screening mammography utilization.

Despite its efficacy, screening mammography is not widely utilized due to various factors. The Health Belief Model (HBM) has previously been used as one conceptualization of relevant patient attitudes. No psychometrically validated measure of these variables has previously been utilized, however, nor have prospective studies of women all of whom have been referred by their physicians for mammography been reported. The research reported here addressed both of those issues. A psychometrically validated measure of the HBM variables, perceived susceptibility, barriers, and benefits, was used, along with age, education, ethnicity, and family breast cancer history to predict mammography utilization in a prospective study of hospital employees. Being white, perceiving fewer benefits of and barriers to mammography, and having a family history of breast cancer were predictive of noncompliance. The avoidant behavior of employees with a family history of breast cancer must be addressed in attempts to increase mammography utilization. In addition, results of the study imply the need for full discussion with women referred for mammography of all issues related to its use, both its benefits and possible barriers.

Adaptation, Psychological↗
PubMed1994

Tamoxifen decreases lipoprotein (a) in patients with breast cancer.

An elevated concentration of lipoprotein(a) [Lp(a)] is a potent risk factor for coronary atherosclerosis. Recently, several hormonal agents including estrogen have been reported to decrease serum Lp(a) concentrations. We found that the antiestrogen tamoxifen also decreased Lp(a) concentrations approximately 40% in six patients with breast cancer, an effect that was achieved by 1 month of therapy and that was stable in five of six patients. If the Lp(a)-lowering effect of tamoxifen can be replicated in women without breast cancer, tamoxifen might be considered as an alternative to niacin for the treatment of elevated Lp(a) levels.

Breast Neoplasms↗
PubMed1994

Limited risk of kidney stone formation during long-term calcium citrate supplementation in nonstone forming subjects.

The physiological and physicochemical effects of long-term calcium citrate supplementation (25 mmol. calcium per day) were assessed in 7 normal premenopausal women. Calcium citrate increased urinary calcium from 3.27 +/- 0.42 mmol. per day (standard deviation) before treatment to 5.16 +/- 0.75 mmol. per day after 1-month of treatment (p < 0.0125). After 3 months of treatment urinary calcium decreased from the 1-month value to 4.54 +/- 0.67 mmol. per day (p < 0.0125) but remained higher than the pretreatment value (p < 0.0125). Fractional intestinal calcium absorption and serum 1,25-dihydroxyvitamin D levels decreased marginally at 1 month of calcium citrate therapy, from 0.457 +/- 0.092 to 0.374 +/- 0.035 (p < 0.05) and from 103 +/- 7 to 77 +/- 14 pmol./l. (p < 0.05), respectively. After 3 months of treatment fractional intestinal calcium absorption decreased further to 0.341 +/- 0.061 (p < 0.0125 compared to pretreatment), whereas serum 1,25-dihydroxyvitamin D remained unchanged at 82 +/- 14 pmol./l. Calcium citrate treatment decreased urinary phosphorus levels significantly from 18.9 +/- 3.3 to 15.0 +/- 2.5 mmol. per day (p < 0.0125) and 14.0 +/- 2.5 mmol. per day (p < 0.05) at 1 and 3 months, respectively. Mean urinary oxalate decreased by 15 to 20% and urinary citrate increased marginally during treatment. Urinary saturation of calcium oxalate and brushite did not change during calcium citrate therapy, except at 1 month when the saturation of calcium oxalate increased marginally. The inhibitory activity of urine against spontaneous nucleation of calcium oxalate and brushite (formation product) did not change during treatment. In conclusion, long-term calcium citrate supplementation in normal subjects does not increase the propensity for crystallization of calcium salts in the urine. This protective effect is probably due to the attenuated increase in urinary calcium excretion (from a decrease in fractional intestinal calcium absorption), a decrease in urinary phosphorus and an increase in urinary citrate.

Adult↗
PubMed1994

Use of Sentinel blood culture system for analysis of specimens from potentially infected prosthetic joints.

The Sentinel blood culture system was used for the analysis of 657 specimens from infected prosthetic joints and blood cultures (83 from prosthetic joints and 574 from standard blood cultures). The positivity rate was similar for specimens from prosthetic joints and blood cultures (18% compared with 14%). However, there was an unacceptable rate of false positive results with specimens from prosthetic joints (58% compared with 8%). This high false positivity rate was due to (i) prolonged incubation and (ii) the lack of blood in these specimens. It is therefore recommended that the Sentinel system should only be used for the initial seven days of incubation of specimens taken from prosthetic joints. Further incubation should take place in a standard incubator and a terminal subculture performed after 21 days.

Bacteria↗
PubMed1994

Tamoxifen and estrogen lower circulating lipoprotein(a) concentrations in healthy postmenopausal women.

Data in the literature suggest that circulating levels of lipoprotein(a) [Lp(a)] and insulinlike growth factor I (IGF-I) respond similarly to therapy with growth hormone, estrogen, or tamoxifen. To more clearly document these relations, we designed a randomized, double-blind, placebo-controlled study of the effects of tamoxifen and continuous estrogen on circulating levels of Lp(a), IGF-I, and IGF binding protein 3 (IGFBP-3) in healthy postmenopausal women. Both estrogen and tamoxifen decreased serum levels of IGF-I to 30% below baseline during the 3 months of treatment, while IGFBP-3 levels were unchanged. Plasma Lp(a) levels decreased to 24% below baseline after 1 month of treatment with either estrogen or tamoxifen (P < .05 for estrogen only); after 3 months Lp(a) decreased to 34% below baseline with tamoxifen therapy (P < .05) but returned to only 16% below baseline with estrogen. The correlation between Lp(a) and IGF-I was highly significant (P < .0001). We conclude that (1) tamoxifen lowers plasma Lp(a) levels in healthy postmenopausal women, (2) the suppressive effects of tamoxifen and estrogen on circulating Lp(a) concentration diverge after the first month of therapy, and (3) circulating levels of Lp(a) and IGF-I are strongly correlated with each other, an indication that they may share regulatory influences.

Aged↗
PubMed1994

Effect of fibrous glass on rat pleural mesothelium. Histopathologic observations.

Female Fisher 344 rats (n = 25) were inoculated intrapleurally with a single 20-mg dose of (JM-100) fibrous glass. The mean length (2.2 microns) and width (0.15 microns) of the fibrous glass particles was within respirable range. Following inoculation, the rats were killed at timed intervals ranging from 2 to 430 d from inoculation. The pleural histopathologic changes were independently observed by a panel of three pathologists blinded to the time elapsed from inoculation. Fibrous adhesions, nodular lesions, and grossly evident tumor were noted in 15, 2, and 1 rat, respectively. In 1 rat there were combined adhesive and nodular changes, and in 6 there were no grossly detectable abnormalities. Chronic inflammation, fibrosis, and foreign body reaction were found in 9, 18, and 10 rats, respectively. Mesothelial hyperplasia and dysplasia were observed in 16 and 9 rats, respectively. Of 16 rats with the severest degree of hyperplasia and dysplasia, 3 developed malignant mesothelioma. This study suggests that a spectrum of rat pleural mesothelial histopathologic changes occurs before development of mesothelioma. The association of severe dysplasia in 3 rats with fully developed mesothelioma suggests that there may be a gradual progression from mesothelial hyperplasia or dysplasia to mesothelioma. Multivariate analysis further suggests that gross pleural nodular lesions and dysplasia may be significantly associated with the development of mesothelioma in this experimental model.

Animals↗