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Biomedical subjects

M Carmichael

Publications and source records attributed to M Carmichael.

15 recordsLinked to original sources
PubMed1996

Ability of biolectric impedance to predict fat-free mass in prepubertal children.

Measurements of body composition are being made increasingly widely in pediatrics. Tetrapolar whole body impedance (BI) is particularly suitable as a method of estimating body composition in children and is therefore the subject of great interest at present. However, the ability of BI to accurately estimate fat-free mass (FFM) in children is unclear, and users of BI are faced with a growing choice of prediction equations for estimation of FFM. Studies in adults have suggested that choice of prediction equation can have a profound effect on the estimate obtained. The aim of the present study was to measure the ability of four published pediatric BI equations to predict FFM in 98 Caucasian prepubertal children (mean age 9.0 y). For three of the published equations, limits of agreement between predicted and reference FFM were wide and distinct biases were apparent. With mean FFM of 25 kg, the equation of L. Cordain et al. overestimated reference FFM (95% CI +2.1 to +3.1 kg), whereas those of P. Deurenberg et al. (95% CI -1.9 to -2.9 kg) and F. Schaefer et al. (95% CI -1.4 to -2.5 kg) systematically underestimated reference FFM. The equation of Houtkooper et al. (95% CI -0.2 to +0.8 kg) predicted FFM with negligible bias and had narrower limits of agreement relative to the reference method than the other three equations tested. We conclude that the ability of BI to predict body composition in children depends on the equation chosen and that the general applicability of BI equations cannot be safely assumed. Cross-validation of BI equations is recommended before they are used routinely for estimation of body composition in children.

Body Composition↗
PubMed1995

OA-519 (fatty acid synthase) as an independent predictor of pathologic state in adenocarcinoma of the prostate.

OBJECTIVES: To improve the prediction of pathologic stage beyond that provided by Gleason score. METHODS: We investigated the tissue expression in prostate cancer of a relatively new marker, oncoantigen 519 (OA-519). Because Gleason score is one of the most powerful predictors in prostate cancer, we restricted our evaluation to 66 radical prostatectomy specimens of varying pathologic stages which were either Gleason score 6 or 7. Immunohistochemical staining of OA-519 was assessed with a combined staining score from 0 to 8, taking into account both the intensity and percentage of tissue staining. In addition, an intensity score was derived based on whether any intense staining was present in case. RESULTS: OA-519 staining of the primary prostate cancer was highly predictive in separating cases with organ-confined disease or capsular penetration versus cases with seminal vesicle invasion or lymph node metastases; Gleason score 6 or 7 was also predictive. In a logistic multivariate regression analysis, both OA-519 and Gleason score were strong independent predictors of pathologic stage (P = 0.0004). CONCLUSIONS: OA-519 predicted pathologic stage well when analyzing primary prostate cancer in radical prostatectomy specimens and is presently being investigated on preoperative biopsy material to assess its ultimate clinical applicability. OA-519 has significant promise as a prognostic marker for prostate cancer and is one of the few markers that provides additional predictive information beyond that of the Gleason score.

Adenocarcinoma↗
PubMed1994

Pathologic and clinical findings to predict tumor extent of nonpalpable (stage T1c) prostate cancer.

OBJECTIVES: We examined preoperative clinical and pathologic parameters in men with clinical stage T1c disease who underwent radical prostatectomy and correlated these findings with the pathologic extent of disease in the surgical specimen in an attempt to identify a subset of patients with potentially biologically insignificant tumor who might be followed up without immediate treatment. DESIGN AND PATIENTS: A case series of 157 consecutive men who underwent radical prostatectomy for clinical stage T1c disease compared with 64 similarly treated clinical stage T1a cancers (incidental minimal cancers found on transurethral resection of prostate) and 439 clinical stage T2 (palpable) cancers. MAIN OUTCOME MEASURES: Pathologic stage, grade, and margins; tumor volume; and tumor location. RESULTS: Sixteen percent of tumors were insignificant (< 0.2 cm3 and confined to the prostate, with a Gleason score < 7); 10% were minimal (0.2 to 0.5 cm3 and confined to the prostate, with a Gleason score < 7); 37% were moderate (> 0.5 cm3 or capsular penetration, with a Gleason score < 7); and 37% were advanced (capsular penetration, with a Gleason score > or = 7 or positive margins, seminal vesicles, or lymph nodes). These findings are intermediate between those found in clinical stage T1a and stage T2 disease. The following parameters were not predictive of tumor extent: age, reason for evaluation, method of detection, and transrectal ultrasound. The best model predicting insignificant tumor was prostate-specific antigen (PSA) density less than 0.1 ng/mL per gram and no adverse pathologic findings on needle biopsy, or PSA density of 0.1 to 0.15 ng/mL per gram, with a low- to intermediate-grade cancer smaller than 3 mm found in only one needle biopsy core specimen. The positive predictive value of the model was 95%, with a negative predictive value of 66%. We accurately predicted 73% of cases with insignificant tumor. CONCLUSIONS: Eighty-four percent of nonpalpable prostate cancers diagnosed by screening techniques are significant tumors and warrant definitive therapy. However, 16% are insignificant. Serum PSA level, PSA density, and needle biopsy pathologic findings are accurate predictors of tumor extent. It may be reasonable to follow up some patients whose tumors are most likely insignificant with serial PSA measurements and repeated biopsies.

Biopsy, Needle↗
PubMed1994

Radical prostatectomy for high grade disease: a reevaluation 1994.

Traditionally, patients with high grade tumors (Gleason score 8 to 10) were not considered candidates for radical prostatectomy because of poor long-term survival rate. However, with improvements in the staging of prostate cancer and a reduction in the morbidity of radical prostatectomy, it is reasonable to reevaluate the results of radical prostatectomy in high grade disease in a contemporary setting. We studied the clinical outcome of 72 men with Gleason scores 8 to 10 on needle biopsy who presented with clinically localized disease (T1c [9], T2a [22], T2b [17], T2c [13] and T3a [11]). Nine patients (13%) did not undergo radical prostatectomy because of positive lymph nodes identified on frozen section. Of the 63 men who underwent radical prostatectomy 43 (68%) had negative lymph nodes and 20 (32%) had positive lymph nodes. The actuarial likelihood of having an undetectable serum prostate specific antigen at 5 years was 43% for men with negative lymph nodes and 45% for men with specimen confined disease. In 7 men (9%) distant metastases developed and all had positive lymph nodes at surgery. These data suggest that men with high grade disease who are suitable candidates for radical prostatectomy should have the pelvic lymph nodes evaluated. If the lymph nodes are negative, the patient may benefit from an attempt at surgical cure.

Actuarial Analysis↗
PubMed1993

Adenocarcinoma of the prostate invading the seminal vesicle: definition and relation of tumor volume, grade and margins of resection to prognosis.

An issue relating to uniformity in pathological staging of prostate cancer that has received relatively minimal attention is that of seminal vesicle invasion. Several studies define tumor in the per-seminal vesicle soft tissue as seminal vesicle invasion, while others equate seminal vesicle invasion with tumor invading the muscular wall of the seminal vesicle. There are also controversies regarding the prognostic significance of seminal vesicle invasion compared to capsular penetration, and whether seminal vesicle invasion is a predictor of poor prognosis independent of tumor volume and grade. We evaluated 115 cases of established capsular penetration, 16 of peri-seminal vesicle invasion and 45 of seminal vesicle invasion in patients without lymph node metastases. Patients with seminal vesicle invasion had a significantly worse prognosis than those with capsular penetration; peri-seminal vesicle invasion was associated with an intermediate risk of progression. Gleason grade, surgical margins and seminal vesicle invasion were all independent predictors of progression in a multivariate analysis, whereas tumor volume was not. In patients with seminal vesicle invasion there was a trend for surgical margins and Gleason grade to predict progression; with tumor volume there was none. Our study demonstrates that the definition of seminal vesicle invasion should be restricted to tumors showing infiltration into the muscular wall of the seminal vesicle. Our study further demonstrates that when assessing the ability of new prognostic variables to predict prognosis of patients with seminal vesicle invasion, margins of resection and Gleason grade should be considered.

Adenocarcinoma↗
PubMed1993

Is tumor volume an independent predictor of progression following radical prostatectomy? A multivariate analysis of 185 clinical stage B adenocarcinomas of the prostate with 5 years of followup.

Tumor volume has been shown to be proportionate to Gleason grade, capsular penetration, seminal vesicle invasion, lymph node metastases and capsular margins of resection. Because these variables are often interrelated, it is crucial to determine which of these parameters provides independent prediction of prognosis in prostate cancer. The current study analyzed 185 men who underwent radial retropubic prostatectomy for clinical stage B adenocarcinoma of the prostate. Patients with seminal vesicle invasion or lymph node metastases were excluded, since these findings are almost invariably associated with progression. All patients were followed for a minimum of 5 years after radical prostatectomy. Only 2 men received postoperative adjuvant therapy. At 5 years after radical prostatectomy 58 men (31%) experienced progression, defined by either an elevated postoperative serum prostate specific antigen level, local recurrence or distant metastases. Although by themselves capsular penetration, tumor volume and per cent of the prostate involved by tumor predicted progression, in a stepwise regression analysis they did not provide independent prognostic information. In this multivariate analysis Gleason score was the best predictor of progression (p < 0.0001); surgical margin was the only other variable that enhanced prediction, although it was less influential than grade (p = 0.018). This strong predictability provided by Gleason score was all the more impressive given the relatively few patients in our study with either low or high grade tumor. Although an accurate preoperative assessment of tumor volume remains desirable for the management of patients with prostate cancer, our study demonstrates that measurement of tumor volume in radical prostatectomy specimens need not be performed as part of the routine pathological analysis of radical prostatectomy specimens, since it does not provide additional information beyond that of Gleason score and the status of capsular margins.

Adenocarcinoma↗
PubMed1993

Corynebacterium group D2 urinary tract infection.

An unusual multiply resistant corynebacterium was isolated from the urine of a comatose patient. This organism was resistant to sulphafurazole, trimethoprim, nalidixic acid, cefazolin, nitrofurantoin, clindamycin, erythromycin, oxacillin, penicillin, gentamicin, amikacin, cinoxacin, ceftazidime and cefotaxime, but was susceptible to ciprofloxacin, ofloxacin, norfloxacin, vancomycin and fucidin. It was identified as the first reported isolate in South Africa of corynebacterium group D2, an organism recently implicated in alkaline-encrusted cystitis and urinary tract infection. We discuss the case history of the patient and review the literature.

Bacteriuria↗
PubMed1992

In vitro antimicrobial susceptibility of viridans streptococci isolated from blood cultures.

The susceptibility of 211 viridans streptococci isolated from blood cultures to eight antimicrobial agents was determined. All the isolates were susceptible to cefotaxime, ceftriaxone, imipenem and vancomycin. Thirty eight percent of the isolates were resistant to penicillin (MICs greater than or equal to 0.25 micrograms/ml). Tetracycline resistance was found in 41% of the isolates and in 7% of these strains tetracycline resistance was combined with erythromycin resistance. Five Streptococcus mitis isolates exhibited increased (MIC 64 micrograms/ml and 128 micrograms/ml) or high-level (MIC greater than or equal to 500 micrograms/ml) resistance to gentamicin, kanamycin and tobramycin. Four of these isolates were also resistant to penicillin (MICs 16-32 micrograms/m). In vitro synergy was not demonstrated for combinations of penicillin and gentamicin against three Streptococcus mitis isolates with gentamicin MICs of 1000, 128 and 64 micrograms/ml. Results of this study indicate the importance of monitoring antibiotic resistance trends in viridans streptococci particularly with respect to penicillin and aminoglycoside resistance.

Drug Resistance, Microbial↗
PubMed1991

Adolescent murderers.

Clinical, developmental and environmental factors were retrospectively studied in 14 adolescent murderers who had been referred to a forensic psychiatric clinic over an 11 year period. Results of these analyses were compared with findings from previous reports. The majority of subjects came from split families. There was a greater than expected degree of psychiatric illness in the adolescents. Previous psychiatric contact, antisocial behaviour and substance abuse were common among these adolescents. A tentative profile of adolescents who are likely to commit murder can therefore be drawn up, which may suggest direction for preventive action and rehabilitation.

Adolescent↗
PubMed1990

Effects of estrogen, androgen, and progestin on sexual psychophysiology and behavior in postmenopausal women.

To assess the contribution of gonadal steroids to sexual behavior in aging women, we conducted a 10-week, double-blind, hormone replacement study of 40 naturally menopausal women (mean age, 58.3 yr). Prospective measurements of basal and stimulated vaginal vasocongestion and daily self-reports of mood, physical symptoms, sexual behavior, and perceived sexual pleasure were collected. Daily treatments were either conjugated equine estrogen, i.e. Premarin (P; 0.625 mg), Premarin and medroxyprogesterone acetate, i.e. Provera (PP; 0.625 and 5 mg, respectively), Premarin and methyltestosterone (PT; 0.625 and 5 mg, respectively), or placebo (PL). Compared to placebo, hormone treatment had significantly reduced hot flashes in the P and PP groups by week 4 and in the PT group by week 5. Headaches were reduced in the P vs. PL group, only. Hormone treatment did not significantly alter mood ratings, sexual behaviors, or psychophysiologically measured sexual arousal. PT treatment significantly increased reports of pleasure from masturbation compared to the other three groups, underscoring the apparent contribution of androgens to self-stimulatory behavior. However, the data suggest that in these physically and sexually healthy women, gonadal steroids do not influence major components of sexual functioning, including arousal and a wide variety of sexual activity and experience.

Analysis of Variance↗
PubMed1983

Infections due to Actinobacillus actinomycetemcomitans. A report of 3 cases.

Three cases are described which show the typical range of infections which may be caused by Actinobacillus actinomycetemcomitans, namely an actinomycosis-like infection, a prosthetic cardiac valve endocarditis and a post-traumatic soft-tissue infection. Cultural studies are detailed, and a short review of the disease-producing potential of this organism and its treatment is presented.

Abscess↗
PubMed1978

Community versus hospital Staphylococcus aureus. Antimicrobial susceptibilities and some features of nasal carriage and acquisition.

Susceptibility of community and hospital isolates of Staphylococcus aureus to 15 drugs has been tested. The organisms were isolated from the noses of White adults admitted to two general surgical units. Approximately half of each group were resistant to beta-lactamase-labile penicillins. Hospital staphylococci displayed a greater degree of multiple drug resistance and resistance to methicillin and erythromycin than did community strains. A nasal carriage rate of 28.6% was found among White patients admitted. A comparative survey of 54 Black adults from a rural community revealed a significantly lower rate (14.8%). On non-carriers admitted to hospital, 21.9% acquired S. aureus nasally.

Anti-Bacterial Agents↗
PubMed1978

Erroneous diagnosis of meningitis due to false-positive gram stains.

During a two-month period, 6% of Gram stains of predominantly CSF specimens revealed gram-negative bacilli with no growth. The source of the false-positive Gram stain results was an alcohol storage bath from which slides were taken and flamed to remove residual alcohol. All 11 patients in the outbreak had further diagnostic tests or changes in therapy. In the laboratory, false-positive slides could be created by contaminating a slide bath with 10(5) bacilli/ml, flame drying, and staining. In addition, contaminated crystal violet caused a false-positive result when applied to a warm but not to a cool slide. To prevent false-positive Gram stain results, the storage of slides in alcohol baths should be abandoned, slides should not be flamed to remove alcohol, and specimens should be Gram-stained only when the heat-fixed slide has thoroughly cooled.

1-Propanol↗
PubMedDate not supplied

Coronary angioplasty in patients who were considered poor bypass surgery candidates.

In most patients who undergo coronary angioplasty (PTCA), coronary bypass surgery (CABG) is an alternative. Patients with severe symptoms secondary to coronary disease, amenable to PTCA, but who are poor CABG candidates are commonly seen. From April 1988 to December 1989 PTCA was performed in 751 patients. Patients with evolving infarction (47) were excluded. Of the remaining 704, 605 were considered candidates for CABG and they were compared to the 99 patients not felt to be candidates for CABG. The objective of this report was to compare these 2 patient groups. These salvage PTCA patients were older, had a higher incidence of heart failure, more prior CABG, higher left ventricular end-diastolic pressure and lower ejection fraction (all p less than 0.01). PTCA had a high success rate per lesion in both groups (96% CABG candidates vs. 95% salvage patients), but there were more patients whose culprit lesion could not be dilated in the salvage group (14% vs. 7%, p less than 0.02). Severe complications including Q wave infarction (2% vs. .3%) and in-hospital death (7% vs. 0.2%) were more common in salvage patients. As planned, emergency CABG was not performed on any salvage PTCA patient but on 2.6% of the other patients. Patients who may benefit from PTCA but were not felt to be operable made up 13% of our PTCA experience. PTCA can be performed in these patients but risks were increased.

Age Factors↗