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Biomedical subjects

J D Johnson

Publications and source records attributed to J D Johnson.

At least 325 records · Page 18Linked to original sources
PubMed1979

Pulmonary excretion of carbon monoxide in the human infant as an index of bilirubin production. I. Effects of gestational and postnatal age and some common neonatal abnormalities.

Using a single pass, flow-through system, the pulmonary excretion rate of endogenously produced carbon monoxide was measured as an index of bilirubin production in human infants with varying gestational and postnatal ages and with a variety of clinical abnormalities. No significant difference in VECO was found related to sex or gestational age. The mean VECO for a small group of Oriental infants was significantly increased. VECO decreased with increasing postnatal age. As expected, infants with hemolytic disease of the newborn had a markedly increased mean VECO. Infants with jaundice of unknown etiology also had an elevated mean VECO, implying that increased bilirubin production may be a factor contributing to the "nonphysiologic" bilirubinemias of these infants.

Bilirubin↗
PubMed1979

Refractory hypoxemia associated with neonatal pulmonary disease: the use and limitations of tolazoline.

Thirty-nine critically ill infants with pulmonary disease received tolazoline because of severe hypoxemia refractory to administration of 100% O2 and mechanical ventilation. Twenty-seven (69%) of the infants responded with an increase in PaO2 greater than or equal to 20 torr in the first umbilical arterial gas after completion of the initial ten-minute infusion (1 to 2 mg/kg) of the drug. A response was not correlated with survival. The overall survival was 46%, essentially unchanged from our previous report (44%). Infants with hyaline membrane disease had the poorest survival rate (33%). Complications associated with the use of tolazoline occurred in 82% of the infants. A hypotensive reaction, defined as a 25% decrease in mean arterial pressure from the pre-tolazoline level, occurred in 67% of the infants, and more commonly in the infants with RDS (87%). In 11 infants who did not respond to the initial dose of tolazoline, the dose was increased up to 10 mg/kg/hour; only one infant responded, and eight (73%) had a hypotensive reaction.

Carbon Dioxide↗
PubMed1979

The white cell ratio in the very low birth weight infant.

The purpose of this study was to assess the usefulness of the white cell ratio of immature neutrophils (PMNs) to total (immature plus mature) PMNs as an indication of infection in the very small premature infant. We retrospectively reviewed the charts of 59 premature infants less than or equal to 1,250 g admitted to our Newborn Intensive Care Unit over a one-year period who had at least one white count determined. Twenty-three were born after rupture of membranes for greater than or equal to 24 hours (PROM), 47 had a one-minute Apgar score less than or equal to 6 and 31 had a five-minute Apgar scores less than or equal to 6, 38 had respiratory distress syndrome (RDS), and 4 had confirmed infection. Thirty-one of the infants had a ratio greater than or equal to .15 in the first day of life, a value which has been suggested in the literature as being abnormal and an indication to suspect sepsis. This ratio bore no statistical relationship to PROM, low Apgar scores, or RDS. We analyzed these same relationships using a ratio greater than or equal to .25, another ratio derived from data in the literature which has been said to suggest infection. No statistical correlation was found for low Apgars or RDS, but there was a significant relationship between PROM and attainment of a ratio greater than or equal to .25 (p less than .005). It is notable that 2 out of the 4 infants with infection had a ratio less than .15. We wish to cast doubt on the applicability of the currently defined WBC ratios in the literature as they apply to the infant with birth weight less than 1,250 g and emphasize the apparent effect of PROM as a factor upon these ratios.

Asphyxia Neonatorum↗
PubMed1979

T-cell subpopulations in chronic lymphocytic leukemia: abnormalities in distribtuion and in in vitro receptor maturation.

Purified human thymus-derived (T) lymphocytes were analyzed by detection of Fc receptors for either IgG or IgM in healthy controls and in patients with chronic lymphocytic leukemia (CLL). There was a significant and persistent increase in the numbers of T cells bearing receptors for IgG (Fc gamma) in CLL patients in comparison to the controls. After an in vitro culture period, there was a significantly decreased appearance of cells with IgM receptors (Fcmu) in CLL patients in comparison to the control group. These results indicate an imbalance in circulating T-cell subpopulations for CLL patients. In addition, an in vitro defect in CLL T-cell membrane receptor appearance is present.

Binding Sites↗
PubMed1979

Effect of erythrocyte destruction on the pulmonary excretion rate of carbon monoxide in adult male Wistar rats.

One of the major contributory factors to hyperbilirubinemia in the human infant is bilirubin production. Determination of the pulmonary excretion rate of carbon monoxide is used to measure indirectly the rate of bilirubin production by estimating the endogenous production of CO, which is formed in equimolar amounts with bilirubin in the catabolism of heme. There has been no study to confirm that complete recovery of CO produced in vivo from the catabolism of known amounts of heme occurs via pulmonary excretion. We report here quantitative determinations of the pulmonary excretion rate of CO in five adult male Wistar rats after injection of known amounts of heme in the form of red blood cells "damaged" by incubation in a solution containing a sulfhydryl inhibitor, NEM. The mean recovery of "extra" CO above baseline production represented as a molar ratio of extra CO to heme was 0.98 +/- 0.02 (S.E.). Control studies showed no extra CO production after starvation, injection of NEM in an amount comparable to that used in the experimental animals, or injection of undamaged red blood cells.

Animals↗
PubMed1979

Pulmonary excretion of carbon monoxide in the human newborn infant as an index of bilirubin production: III. Measurement of pulmonary excretion of carbon monoxide after the first postnatal week in premature infants.

Using a single pass, flow-through system, the excretion rate of endogenously produced carbon monoxide (VeCO) was measured as an index of bilirubin production in 41 Caucasian infants of various gestational ages after the first postnatal week. twenty-one were less than or equal to 32 weeks gestation. The mean slope for the 25 premature infants with multiple VeCO determinations was -0.21 +/- 0.11 (SE) microliters/kg/hour per day (P less than .025, one-tailed). Fifteen premature infants with at least three VeCO determinations during the first 30 days of life had an average decrease in total CO excreted of 1.33% per day compared to the extrapolated initial value of total CO excretion of 27.0 +/- 2.0 (SE) microliters/hour, giving a calculated maximum red cell life span of 75 days.

Bilirubin↗
PubMed1978

Flunisolide nasal spray in the treatment of perennial rhinitis.

In an 8-week double-blind study of the clinical effectiveness of flunisolide, a new synthetic corticosteroid intended for topical use, 73 persons with perennial rhinitis received 300 microgram/d of either flunisolide or placebo. The flunisolide group showed a significantly greater reduction than the placebo group in the daily duration of sneezing, stuffy nose, nose blowing and postnasal drip, but not of runny nose, and a significantly greater reuction in the severity of all these manifestations. Substantial or total control of manifestations was reported by 73% of the flunisolide group and 25% of the placebo group, a significant difference. Careful monitoring of the plasma cortisol concentration revealed no evidence of adrenal suppression, and in no patient did the value fall below normal. The lack of adrenal suppression may be due to the very small amount of corticosteroid administered and the rapid metabolism of flunisolide into a relatively inactive metabolite.

Administration, Intranasal↗
PubMed1978

Dansylaziridine-labeled troponin C. A new fluorescent "physiological" probe for calcium regulation by sarcoplasmic reticulum.

Dansylaziridine-labeled troponin C (TnCDANZ) undergoes a greater than 2-fold fluorescence enhancement with Ca2+ binding to the Ca2+-specific regulatory sites of troponin C. Hence, TnCDANZ serves as a very good indicator of Ca2+ in the range of 3.0 to 70 micron. Ca2+ uptake and release by sarcoplasmic reticulum can be easily and accurately monitored by the fluorescence changes in TnCDANZ. In this manner, we can monitor directly the removal of Ca2+ from troponin C by the sarcoplasmic reticulum. Thus, this reaction represents a useful analogue ot the Ca2+ "on-off" process in muscle.

Animals↗
PubMed1978

Detection of two classes of Ca2+ binding sites in troponin C with circular dichroism and tyrosine fluorescence.

We have observed a biphasic increase in [theta]222 and the tyrosine fluorescence of troponin C (TnC) with increasing [Ca2+]. Approximately 62% of the total helical change and 81% of the total increase in tyrosine fluorescence occurred with Ca2+ binding to a class of sites with a KCa of approximately 2.7 X 10(7) M-1. The remaining spectral changes occurred with Ca2+ binding to a class of sites with KCa of approximately 3.1 X 10(5) M-1. We interpret these biphasic responses in terms of distinct structural changes occurring in TnC with Ca2+ binding to the high affinity (KCa approximately 2.1 X 10(7) M-1) Ca2+-Mg2+ sites and to the low affinity (KCa approximately 3.2 X 10(5) M-1) Ca2+-specific regulatory sites.

Binding Sites↗
PubMed1978

Lactose malabsorption among adult Indians of the Great Basin and American Southwest.

The prevalence of primary adult lactose malabsorption and the pattern of milk use were studied among 109 Indians from various tribes of the American Great Basin and Southwest. Included were 100 persons who reported being full-blooded Indians as well as three with Mexican admixture and 6 with some European ancestry. Lactose malabsorption was found in 92% of the full-blooded Indians but in only 50% Indians who acknowledged European admixture. These results agree with those of studies of native Americans done elsewhere which show very high prevalences of such lactose malabsorption among adults reported as fullblooded and lower prevalences among individuals with admitted European ancestors. The suggestion made is that in pre-Colombian times, before interbreeding with Europeans began on any scale, such lactose malabsorption may have been nearly universal among native American adults. Most of the Indians studied consumed abundant milk since childhood but were nevertheless predominantly malabsorbers as adults. This argues against the induction hypothesis advanced by some to explain the striking ethnic differences that occur around the world in primary adult lactose malabsorption.

Adult↗
PubMed1978

Double-blind trial comparing flunisolide and placebo for the treatment of perennial rhinitis.

The effectiveness of a new topical steroid, flunisolide, was evaluated for the treatment of patients with perennial rhinitis. The sixty-nine patients in this 8 week double-blind parallel trial received either 300 microgram/day of flunisolide or placebo. The flunisolide group showed statistically greater improvement than the placebo group in such symptoms as the duration of sneezing, stuffy nose, runny nose and nose blowing. 63% of the flunisolide group compared with 39% of the placebo group felt the test spray had provided substantial or total control of their nasal symptoms (P = 0.0026). When those patients who were skin test-positive (allergic) were considered separately from those who were skin test-negative (non-allergic), differences in responsiveness were noted. While those patients who had negative skin tests received greater relief of their symptoms with flunisolide than with placebo, patients who had positive skin tests showed a greater responsiveness to flunisolide and reported a higher incidence of significant or total control of their symptoms. Careful monitoring of plasma cortisol levels revealed no evidence of adrenal suppression in any of the patients in this trial. This lack of suppression may be due to two factors: (a) flunisolide is rapidly metabolized into a metabolite with a low degree of activity and (b) a very low dose of corticosteroid is administered.

Adolescent↗
PubMed1978

Flunisolide nasal spray for the treatment of children with seasonal allergic rhinitis.

Forty-eight children with seasonal allergic rhinitis received either 150 microgram/day of flunisolide (a new topical steroid) or placebo. Those receiving flunisolide had a significantly shorter daily duration of sneezing, stuffy nose, runny nose and throat itch. Total or substantial control of their symptoms was reported by 67% of the flunisolide group and 25% of the placebo group.

Administration, Intranasal↗