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Biomedical subjects

V Stevens

Publications and source records attributed to V Stevens.

34 records · Page 2Linked to original sources
PubMed1987

A double-blind comparative study of alprazolam and dothiepin hydrochloride in the treatment of anxiety associated with depression.

One hundred patients with mixed symptoms of anxiety and depression were enrolled into a prospective, multi-centre, randomized, double-blind study comparing the response to, and the side-effects of, alprazolam and dothiepin hydrochloride over 4 weeks of treatment. Mean daily doses were 2.33 mg alprazolam and 115 mg dothiepin. Data on 96 patients were evaluated for tolerance, and data for 85 patients were analyzed for therapeutic response. In each case, the groups were similar in numbers, mean ages and sex ratios. Both groups experienced satisfactory responses to therapy, with highly statistically significant changes (p less than 0.001) in the means of all efficacy measures within each group. No statistical difference was demonstrated in favour of either treatment group. Both dothiepin and alprazolam exhibited a similar profile of mild minor side-effects, but more patients suffered moderate to severe reactions to dothiepin, leading to a greater drop-out rate in the dothiepin-treated group. It is concluded that, as both treatments produced equally satisfactory responses in this study, alprazolam should be considered for the treatment of anxiety associated with depression in patients for whom tricyclic antidepressant drugs are either contra-indicated or poorly tolerated.

Adolescent↗
PubMed1985

Respiratory and heart rate patterns in infants destined to be victims of sudden infant death syndrome: average rates and their variability measured over 24 hours.

From a prospective study in which 24 hour recordings of the electrocardiogram and respiratory activity (abdominal wall movement) were made on a population of full term infants, 22 recordings were obtained from 16 infants who later were victims of the sudden infant death syndrome. The average heart rate, average heart rate variability, average breath to breath interval, and average breath to breath interval variability over the whole of each recording for the 22 recordings were compared with those from a control group of 324 infants selected at random from the rest of the population. No significance was found in the number of recordings from those infants who suffered the sudden infant death syndrome which lay outside the 5th-95th percentile range of the control group for the four variables studied. In a group comparison no difference was found between the sudden infant death syndrome group and the controls either in terms of the respiratory variables studied or in terms of the average heart rate variability. The results did, however, suggest that there may be a group difference in terms of the average instantaneous heart rate.

Age Factors↗
PubMed1985

Analysis of the heart rate and breathing patterns of infants destined to suffer sudden infant death syndrome: probability density function analysis.

From a prospective study into the sudden infant death syndrome in which 24-h recordings of the ECG and respiratory waveform (abdominal wall movement) were made on a population of full-term infants, 22 recordings were obtained on 16 infants who subsequently suffered sudden infant death syndrome. The probability density function for the instantaneous heart rate and the breath to breath intervals and their randomly variabilities were calculated for these 22 recordings and for a control group of 324 infants randomly selected from the remainder of the population. A principal components analysis was then performed to classify the data and to make comparisons between infants. The infants in the analysis were divided into three postnatal age groups. No differences were found between the sudden infant death syndrome cases and the control group for the breath to breath intervals and its variability or for the instantaneous heart rate. Three sudden infant death syndrome cases lay outside the range of values for the heart rate variability at 6 wk of age.

Age Factors↗
PubMed1984

High concentrations of furosemide inhibit serum binding of thyroxine.

Serum samples taken from four patients who had low serum T4 concentrations (less than 2 micrograms/dl) during severe non-thyroidal illness were found to contain a heat-stable, dialyzable inhibitor of 125I T4 binding to plasma proteins. Inhibitory activity coincided with high dose furosemide treatment for oliguric renal failure. Inhibition was proportional to the serum furosemide concentration and the effect was reproduced in vitro by addition of furosemide to normal serum. The inhibitory effect diminished with serum dilution while maintaining the same relative concentration of furosemide. A time-course study in one patient demonstrated a close temporal relationship between high serum concentrations of furosemide and subnormal T4, associated with T3 resin uptake values compatible with increased occupancy of T4-binding globulin by a competitor. These findings demonstrate that furosemide in high concentrations can inhibit T4 binding in plasma and may be a factor contributing to the development of the low T4 state in critical illness.

Acute Kidney Injury↗
PubMed1983

"Unbound analog" radioimmunoassays for free thyroxin measure the albumin-bound hormone fraction.

We have assessed the influence of albumin-bound thyroxin (T4) on apparent free T4 values obtained by two "unbound analog" free T4 methods (AmerlexR Free T4 and Clinical Assays one-step Free T4). We evaluated sera showing three different albumin anomalies: total hereditary analbuminemia, partially corrected analbuminemia, and familial dysalbuminemic hyperthyroxinemia, where abnormal albumin-binding of analog tracer is associated with high apparent free T4 values by these methods. In hereditary analbuminemia, free T4 was almost undetectable by both assays; in contrast, free T4 by equilibrium dialysis was normal. After addition of T4-free human serum albumin, the apparent free T4 concentration in total hereditary analbuminemia became normal by the analog methods. Immunoprecipitation of [125I]T4 and the unidentified labeled kit analogs by antiserum to human albumin was negligible in untreated total hereditary analbuminemia and approximately twice normal in familial dysalbuminemic hyperthyroxinemia. Therefore, alterations in tracer binding to albumin correlate with the apparent free T4 concentrations obtained by the analog methods. The interactions of the unidentified analog tracers and T4 with albumin are such that these techniques principally reflect the albumin-bound T4 moiety.

Antigen-Antibody Complex↗
PubMed1982

Biochemical composition of muscle in normal and semistarved human subjects: relevance to anthropometric measurements.

Anthropometric methods aimed at assessing muscle size in undernourished subjects assume a constant proportionality between the mass (i.e., size) and composition (specifically protein-energy content) of this tissue. This assumption was examined in three autopsy groups: controls (n = 11, sudden traumatic death), early semistarvation (n = 6), acute preterminal disease), and chronic semistarvation (n = 34, severe weight loss over time). Results of semistarved groups were expressed relative to respective control value. Early semistarvation produced no detectable change in muscle mass, protein, or total energy content (per gram wet weight), although RNA and glycogen were -50 to -70% of control value (p less than 0.05). Chronic semistarvation caused muscle atrophy (-54.2%), but not all measured constituents were reduced to the same degree. The results were H2O--52.9%, collagen--46%, noncollagen proteins--65.3%, total lipids--40%, DNA--54.1%, RNA--81.7%, glycogen--90.3%, and total energy--59.6%. Muscle per unit mass in chronic semistarvation thus reflects relatively more H2O and less protein and energy when compared to normal tissue. About 85 to 95% of muscle protein-energy loss can be detected by anthropometric measurements of muscle size; the remaining 5 to 15% depletion of protein and energy is masked by muscle compositional changes. Proper interpretation of anthropometric data requires an understanding of these unmeasured but important compositional differences in normal and semistarved muscle.

Anthropometry↗
PubMed1982

Anthropometric measurement of muscle mass: revised equations for calculating bone-free arm muscle area.

Arm muscle area (AMA, cm2) is currently calculated from triceps skinfold thickness (TSF, cm), and midarm circumference (MAC, cm). In assessing the accuracy of the current equation by comparison to AMA measured by computerized axial tomography, error in each of the four approximations made was found to result in a 20 to 25% overestimate of AMA. Two correctible error sources were: a 10 to 15% overestimation caused by assuming a circular midarm muscle compartment and a 5 to 10% overestimation due to inclusion of midarm cross-sectional bone area. Corrected AMA equations for men and women were respectively: [(MAC - pi x TSF)2/4 pi] - 10, and [MAC - pi x TSF)2/4 pip] - 6.5. With two additional study groups, the overall improved accuracy of the new equations was confirmed, although the average error for a given patient was 7 to 8%; the relationship between corrected AMA and total body muscle mass was established [muscle mass (kg) = (ht, cm2) (0.0264 + 0.0029 x corrected AMA)]; and the minimal range of corrected AMA values compatible with survival (9 to 11 cm2) was defined. Bedside estimates of undernutrition severity and prognosis can therefore be calculated from two simple measurements, TSF and MAC.

Adult↗
PubMed1975

In vitro production of erythropoietin by mouse fetal liver.

Mouse fetal liver tissue has been cultured and shown to produce and release into the culture medium an erythropoietically active substance for up to 30 days of culture. Since this substance can be completely neutralized by an antiserum to erythropoietin and shows a dose--response relationship in the plethoric mouse assay, it is suggested that the culture medium contains erythropoietin, a hormone important in the regulation of erythropoiesis. Using this procedure, we have obtained the equivalent of about 20.7 unites of erythropoietin from five T-flasks (75 sq cm) over the 30-day culture period.

Animals↗
PubMedDate not supplied

Late luteal rescue in the baboon (Papio cynocephalus).

Numerous studies have used human chorionic gonadotrophin (HCG) administration to study the response of the primate ovary to gonadotrophin stimulation. These studies are generally performed in the luteal phase with very few studies of the follicular phase. We have studied the effect of both HCG and gonadotrophin releasing hormone (GnRH) agonist administered at the early follicular phase in normally cycling baboons (Papio cynocephalus). Five baboons were treated with increasing doses of HCG for 5 consecutive days starting on day 1 of the cycle and three untreated baboons served as controls. Follicular and luteal phase lengths were determined and serum samples were assayed for progesterone, oestradiol and 17alpha-OH progesterone. In a separate study, six baboons were treated with GnRH agonist (WY-40972) on days 2-6 of the cycle and saline-treated baboons served as controls (n = 5). Mean peak progesterone concentrations (+/- SE) during the treatment interval were 3.88+/-0.56 ng/ml in HCG-treated baboons compared to 0.19+/-0.07 ng/ml in controls (P < 0.001). A similar significant increase (P < 0.001) in serum 17alpha-OH progesterone concentrations was also observed (6.13+/-1.12 ng/ml versus 1.13+/-0.49 ng/ml). In association with the increase in luteal steroids there was also a significant prolongation of menstrual cycle length from 32.7+/-1.2 days in controls to 46.8+/-4.9 days in HCG-treated baboons (P < 0.05), which involved prolongation of the follicular phase (16.7+/-1.2 days to 29.0+/-4.6 days; P < 0.05) with no difference in luteal phase length or progesterone concentrations. In GnRH agonist-treated baboons, mean (+/- SE) cycle length was prolonged to 46.3+/-1.6 days and in saline-treated controls was 32.8+/-0.8 days (P < 0.001), again this was completely represented by the change in follicular phase length, from 13.4+/-0.7 days in controls to 27.2+/-2.1 days in agonist-treated baboons (P < 0.001). In contrast, there was no significant difference in luteal phase length between these two groups (19.4+/-0.7 versus 19.2+/-1.0 days). The prolongation of the follicular phase was accompanied by significant increases in both progesterone (P < 0.01) and oestradiol (P < 0.01) during GnRH agonist treatment above control concentrations. Luteal phase concentrations of these hormones were not different from controls. These results demonstrate the previously unreported finding that gonadotropin stimulation will rescue the corpus luteum in the next follicular phase.

Animals↗
PubMedDate not supplied

The impact of the ageing population on intensive care provision.

This paper explores the impact of the ageing population on the health service and intensive care provision. The concept of rationing is discussed. The paper concludes that age alone is not a reliable prediction of outcome (e.g. length of stay; mortality). The review highlights the lack of literature available offering a comparison of costs associated with intensive care management of the elderly.

Aged↗