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Biomedical subjects

B Nelson

Publications and source records attributed to B Nelson.

At least 91 records · Page 5Linked to original sources
PubMed1988

Abnormalities of urine urobilinogen and urine bilirubin assays and their relation to abnormal results of serum liver function tests.

A prospective observational study of 324 cases was conducted in a busy ambulatory care setting to evaluate the sensitivity, specificity, predictive values, and accuracy of spot urine urobilinogen and urine bilirubin assays as screening tests for serum liver function test (LFT) abnormalities. High positive predictive values (88% for at least one abnormal LFT) make the evaluation of positive urine screens detected during routine health care maintenance examinations imperative. Because extraneous factors may influence both urine and serum test results, however, urine assays obtained as a screening parameter in clinical presentations (abdominal pain, jaundice, constitutional symptoms, etc) have only limited clinical utility. The high proportion of false-negative results for both urine assays renders their statistical properties unacceptable as screens in these clinical situations.

Adolescent↗
PubMed1988

Vibrio vulnificus septicemia.

We report a case of Vibrio vulnificus infection in a middle-aged alcoholic man with Laennec's cirrhosis. The patient had recently received a puncture wound from the shell of a shrimp while fishing in the Gulf of Mexico. He presented with acrally distributed urticarial plaques, purpura, and bullae, as well as signs and symptoms of septic shock. Vibrio vulnificus was isolated from the blood, and histologic examination of the skin biopsy specimen demonstrated a devitalized, inflammatory, cell-poor superficial dermis and an acute cellulitis of the subcutis, with extensive tissue destruction. In addition, a necrotizing vasculitis, with a relative paucity of inflammatory cells but numerous bacilli around dermal vessels, was noted.

Humans↗
PubMed1987

Electroencephalographic sleep of adolescents with major depression and normal controls.

Forty-nine, mostly outpatient (86%), nonbipolar adolescents, aged Tanner stage III to 18 years, with a current diagnosis of major depressive disorder and 40 adolescents without current presence or history of psychiatric disorder were studied polysomnographically for three consecutive nights. Sleep latency was significantly longer in the depressive groups. The nonendogenous depressive patients exhibited significantly more awake time and lower sleep efficiency during the sleep period. No significant group differences were found for first rapid eye movement (REM) period latency, REM density, or any other REM sleep measures. Age correlated significantly with REM latency and delta sleep time, especially among depressive patients. No significant correlations between sleep measures and severity of illness were found. It appears that the classic REM sleep findings associated with the adult depressive syndrome are not present among depressive adolescents, indicating a later ontogeny for these abnormalities.

Adolescent↗
PubMed1987

The clinical picture of major depression in children and adolescents.

Symptom frequency and severity were compared in two sequential clinically referred samples of 95 children and 92 adolescents, aged 6 to 18 years, all medically healthy, assessed with the Schedule for Affective Disorders and Schizophrenia for School Age Children, Present Episode, who met unmodified Research Diagnostic Criteria for major depressive disorder (MDD). There were no significant differences between the two groups in the majority of depressive symptoms. However, prepubertal children had greater depressed appearance, somatic complaints, psychomotor agitation, separation anxiety, phobias, and hallucinations, whereas adolescents had greater anhedonia, hopelessness, hypersomnia, weight change, use of alcohol and illicit drugs, and lethality of suicide attempt, but not severity of suicidal ideation or intent. Adolescents with a duration of the depressive episode of two years or greater had significantly higher rates of suicidal ideation and intent, lethality, and number of suicide attempts than youngsters with depressive episodes of shorter duration. A principal components factor analysis of psychiatric symptoms was carried out in all 296 youngsters evaluated during the same period who met DSM-III criteria for any Axis I diagnosis. The majority had an affective disorder. Factors were quite similar for both adolescents and children and included an "endogenous" and an "anxious" factor, as in many studies of adult depression. In addition, three other factors were found: negative cognitions, appetite and weight changes, and a conduct factor. Suicidal ideation was a component of both the negative cognitions factor and the conduct factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

The relationship of the dexamethasone suppression test (1 mg and 2 mg) to basal plasma cortisol levels in endogenous depression.

The 1 mg and 2 mg dexamethasone suppression tests (DST) were evaluated in two groups of endogenously depressed patients (n = 39 and n = 30, respectively) who also had a 1300-1600 hr basal cortisol assessment. Non-suppressors (on both DSTs) had significantly higher basal plasma cortisol levels and thus were significantly associated with relative cortisol hypersecretion. However, there was only a partial overlap between DST response and basal plasma cortisol, with a large variation of cortisol levels among non-suppressors. The 2 mg DST appears to be more specific for cortisol hypersecretion than the 1 mg DST. If cortisol hypersecretion is to be identified, neither the 1 mg or 2 mg DST is an adequate assessment nor a substitute for a basal cortisol assessment.

Adult↗
PubMed1986

Rapid diagnosis of group A strep pharyngitis in the emergency department.

Two ten-minute rapid tests for diagnosing Group A streptococcal pharyngitis in 147 emergency department patients with a complaint of sore throat were evaluated using positive throat cultures as the marker for disease. Treatment was initiated solely on the basis of clinical judgment. Sensitivity and specificity were 78% and 93%, respectively, for the rapid test and 69% and 56%, respectively, for clinical judgment. The rapid test was significantly better than clinical judgment alone in determining the presence of disease (P less than .05). The predictive values of the positive and negative and were 78% and 93%, respectively, for the rapid test and 38% and 85%, respectively, for clinical judgment. In the ED setting in which adequate followup is difficult, the rapid test can identify more accurately than can clinical judgment alone those patients who need therapy.

Antigens, Bacterial↗
PubMed1985

The cortisol response to desipramine in endogenous depressives and normal controls: preliminary findings.

Plasma cortisol levels were monitored for 2 hours after an intramuscular injection of 75 mg desipramine in 13 endogenous depressives and 20 normal controls. Endogenous depressives had a significantly reduced cortisol response in comparison to normal controls, not explained by sex, age, or baseline cortisol differences between groups. A lack of a cortisol rise of 1.5 micrograms/dl above baseline by 45 minutes discriminated best, with 7 of 13 depressives (55%) being identified in contrast to only 1 of 20 normals (5%). The results suggest that this may be a useful biological test with acceptable sensitivity (55%) and excellent specificity (95%). Furthermore, these data suggest that norepinephrine may be stimulatory to cortisol in man.

Adult↗
PubMed1985

Characterization of the chromophore of the third rhodopsin-like pigment of Halobacterium halobium and its photoproduct.

Halobacterium halobium contains at least three retinal-containing pigments: bacteriorhodopsin, halorhodopsin, and a third rhodopsin-like pigment (tR) absorbing at approximately 590 nm, tR590. Illumination of tR590 gives rise to a very long-lived blue absorbing photoproduct, tR370. Using high-performance liquid chromatography we show that the chromophore of tR590 is primarily all-trans retinal and its conversion by light to tR370 causes the chromophore to isomerize primarily to the 13-cis conformation. Irradiation of the tR370 gives rise to a transient photoproduct absorbing at approximately 520 nm that decays back to the initial pigment tR590. In addition to all-trans retinal, the apomembrane of tR can also combine with 13-cis retinal but not with the 9- or 11-cis isomers.

Bacteriorhodopsins↗
PubMed1985

Oxygen consumption in mice (I strain) after feeding.

To determine if excess heat production can account for the lower fat accumulation in I strain mice, oxygen consumption, a measure of energy expenditure, was measured in I mice and C57BL mice (a control strain) to determine basal metabolic rate (BMR) and resting metabolic rate (RMR) and response to food consumption and acute cold exposure. Oxygen consumption was higher in the I strain than in the C57BL mice only after the dark cycle (feeding period). No difference between I and C57BL mice in spontaneous activity was found during the dark or light cycle. Body temperature was also not different in I and C57BL mice. Oxygen consumption in response to norepinephrine was similar in the two strains. These results indicate oxygen consumption is greater in I than C57BL mice only in response to feeding. Differences in glucose utilization by I and C57BL mice, including a lower glucose tolerance curve, greater deposition of glucose to muscle glycogen and lactate production in I mice also indicate differences in nutrient processing. Higher oxygen consumption after feeding in I mice than in C57BL mice indicates inefficient food utilization and accounts for their lower ability to store energy as fat.

Animals↗
PubMed1985

Microglandular hyperplasia of the uterine cervix.

Forty-three cases of microglandular hyperplasia of the cervix seen during a 3.5-year period are reported. The series is unusual in that more than one-half of the patients had no history of oral contraceptive use and three patients were postmenopausal. Additionally, evidence of estrogenic stimulation was present in eight cases. The role of estrogens and progestogens in the development of microglandular hyperplasia is discussed. The authors consider microglandular hyperplasia to be an unusual and florid form of reserve cell hyperplasia with glandular differentiation.

Adult↗
PubMed1982

Simultaneous determination of hydrocortisone and benzyl alcohol in pharmaceutical formulations by reversed-phase high-pressure liquid chromatography.

An accurate, reproducible, and specific reversed-phase high-pressure liquid chromatographic (HPLC) procedure that simultaneously determines hydrocortisone and benzyl alcohol in a variety of pharmaceutical formulations is presented. Cream, gel, ointment, and solution formulations containing varying hydrocortisone and benzyl alcohol concentrations can be analyzed with only minor modifications in sample preparation. To provide optimum accuracy and reproducibility, phenethyl alcohol is used as an internal standard. The specificity of the procedure allows for the quantitative determination of hydrocortisone and benzyl alcohol in the presence of their degradation products and without interference from the phenethyl alcohol. The determinations can be performed with an analysis time of 10-13 min/sample.

Benzyl Alcohol↗
PubMed1982

Respiratory pauses and apnea during daytime sleep in normal infants during the first year of life: longitudinal observations.

Respiratory pauses (3-10 sec in duration), apnea (less than 10 sex in duration), and periodic respiration observed in thoracic respirograms were measured in 226 polysomnograms obtained on 17 normal infants during the first year of life. All subjects had one or more respiratory pauses in a majority of recordings; 35% had respiratory pauses in all recordings; 75% of respiratory pauses were associated with body movement. There is marked intersubject and even intrasubject variability in respiratory pause rates. The range of mean respiratory pause rates among subjects was 2.0 - 14.4/h, and for single recordings was 0.0 - 43.6/h. Their occurrence was directly related to the occurrence of periodic respiration. Rates were higher during REM and indeterminate sleep than during slow wave sleep. There was no significant trend toward increase or decrease in respiratory pause rate during the first year post term. Apnea occurred in only one of the 226 recordings (0.4%). Periodic respiration occurred in 8 of 17 subjects (47%), and in 25 of 226 recordings (11%). Its occurrence was unrelated to sleep stage. The following conclusions are considered valid on the basis of the data presented and reports in the literature: (1) Rates of respiratory interruption are higher before than after 40 weeks conceptional age. (2) There is considerable intersubject variability in rates of respiratory interruptions. (3) Respiratory pauses are common during sleep in normal human infants. (4) Respiratory pauses occur more frequently with movements than in their absence. (5) Respiratory pause rates are higher during REM sleep than during slow wave sleep. (6) Apneas of greater than 10-15 sec duration do occur in normal infants, but are rare. From the clinical viewpoint, respiratory pauses (less than 15 sec) of the central type, regardless of abundance, and periodic respiration cannot by themselves be used as evidence that a baby is at risk of anything. The occurrence of apneas (greater than 15 sec duration), especially if any are of the obstructive or mixed types (and perhaps respiratory pauses of the obstructive and mixed types), and/or if associated with bradycardia or decrease in oxygen saturation, indicate sleep apnea syndrome and suggest risk of sudden infant death.

Circadian Rhythm↗