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Biomedical subjects

G Alexander

Publications and source records attributed to G Alexander.

At least 91 records · Page 5Linked to original sources
PubMed1990

Geographic after-tax real income differentials and population growth rates.

"The purpose of this [one-page] note is to empirically investigate the impact of geographic after-tax real income differentials on geographic population growth rate differentials. The focus is on population growth rates in Florida's 67 counties over the period 1980-88." The authors conclude that "even after allowing for a variety of other location-influencing factors, including coastal access, after-tax real income differentials exercise a positive and significant impact on population growth rate differentials among Florida's counties."

Americas↗
PubMed1990

Causes of infant mortality in a multiethnic population.

Causes of infant mortality and their change over time in five ethnic groups were investigated using linked infant death and live birth certificates from the State of Hawaii, 1968-1983. Over the study period, there were 3,324 deaths of which 31 percent were to Whites, 26 percent to Hawaiians, 17 percent to Asians, 15 percent to Filipinos and 10 percent to other ethnic groups. Significant changes in the proportion of deaths by cause occurred over the period. Perinatal causes remained the most frequent, but their relative contribution to annual infant deaths declined from 61 percent to 47 percent. The proportion of deaths from congenital anomalies increased from 19 percent to 30 percent, while the proportion of deaths from infectious diseases declined from 14 percent to 4 percent. There was a significant difference in the proportion of deaths by cause between ethnic groups in the early years of the study period. However, during the last four years 1980-1983, no significant difference between ethnic groups was observed.

Asia↗
PubMed1990

Effect of prolonged glucose infusion into fetal sheep on body growth, fat deposition and gestation length.

Eleven Merino sheep fetuses were supplemented with glucose by direct continuous intravenous infusion of 50% dextrose into the fetus from day 115 of gestation until spontaneous delivery. Infusion rates of 15 or 25 g/day per kg were used and equivalent volumes of saline were infused into 11 control fetuses. Infusion periods approximated 27 days in both groups. Fetal plasma glucose concentrations were significantly (P less than 0.001) elevated throughout glucose infusion and resulted in variable but consistently higher plasma insulin concentrations in the glucose than in the saline-infused fetuses. Glucose-infused fetuses were significantly heavier than controls (mean +/- SEM; 3.86 +/- 0.16 vs 3.28 +/- 0.24 kg, P less than 0.05) and body fat depots (in g/kg body wt.) were larger in glucose-infused than control fetuses (9.91 +/- 0.65 vs 6.73 +/- 0.37, P less than 0.005, for internal brown fat depots; 1.25 +/- 0.44 vs 0.27 + 0.13, P less than 0.05, for subcutaneous white adipose tissue). The results indicate that growth and lipid deposition in the sheep fetus are responsive to increased glucose supply, an effect which may be mediated through the actions of insulin. Mean gestation length was 146.60 +/- 1.45 days for controls and 144.18 +/- 1.23 days for glucose-infused animals (normal term 150 days).

Adipose Tissue↗
PubMed1989

Treatment of acute and chronic viral hepatitis.

Over the 12 years since the first introduction of interferon for the treatment of chronic hepatitis B, progress has apparently been slow. Nevertheless, it now appears that at least one third of chronic hepatitis virus carriers, particularly those with more severe disease, and a similar, perhaps greater, proportion of those with chronic parenteral non-A, non-B hepatitis, can be successfully treated with alpha-interferon. In the not too distant future, controlled trials of alpha-interferons in these situations will be complete and they will be a yardstick by which other future therapies can be judged. Already a number of trials are in progress to determine which agents might, in addition to interferon, augment the response rates. The situation clinically is analogous to that for tuberculosis in the 1950s and for cancer chemotherapy only a decade or so ago. The prospects of prevention of the progression to cirrhosis, and perhaps in the long term reduction in the incidence of hepatocellular carcinoma, are exciting, and with the introduction of a number of new cytokines available through recombinant technology, each with novel antiviral activities, the future prospects are exciting indeed.

Acute Disease↗
PubMed1989

Predicting depression using earliest childhood memories.

In order to investigate the utility of earliest childhood memories (EMs) in clinical assessment, this study investigated the value of EMs in predicting naturally occurring depressive mood states. Of interest were those features of EMs that discriminate depressed from nondepressed individuals. Subjects were 212 undergraduate volunteers who completed the Beck Depression Inventory, the Profile of Mood States, and a self-administered EM questionnaire. Utilizing thematic predictors derived from cognitive and psychodynamic theories of depression, depressed subjects were differentiated from nondepressed subjects at a rate significantly greater than chance, p less than .001, with a highly respectable estimate of cross-validation shrinkage. The findings demonstrate the phenomenon of mood dependent recall in autobiographical memory, namely, that memory attributes are strongly influenced by current mood state. Consistent with psychodynamic theories of depression and in contrast to cognitive theory, depressive mood states appear to facilitate retrieval of memory schemas involving deprivation and disturbing human interaction. Schemas involving loss of control, failure, or reactions to noncontingent reinforcement (perceptions of the self as agent) appear less salient than relationship schemas (perceptions of the self as related) in depressive experience.

Adolescent↗
PubMed1989

Pharmacist-based i.v. theophylline therapy.

With the support and guidance of the medical staff, a protocol for IV theophylline dosing and monitoring has been implemented. The patients' theophylline needs are individually determined by pharmacists using clinical criteria and historical data determined for each patient. Ongoing monitoring and dosage adjustments are provided. The protocol is described where a therapeutic range of 10-20 mcg/mL was maintained 84% of the time as verified by quality assurance audits.

Adolescent↗
PubMed1989

Umbilical artery flow velocity waveform analysis in normal ovine pregnancy and after carunculectomy.

Twenty fetal lambs were studied in utero using continuous wave Doppler ultrasound to analyse the fetal umbilical artery flow velocity waveforms. Satisfactory waveforms were obtained. Prepregnancy surgical removal of uterine caruncles was used to produce intrauterine fetal growth retardation in 14 of these ovine pregnancies of whom 8 delivered a small for gestational age fetus. In only one fetus was the umbilical artery flow velocity waveform abnormal with a high systolic diastolic ratio. We conclude that the growth restriction occurring in the ovine fetus following a reduction of placental implantation sites is not related to a restriction in the fetoplacental circulation and this is different from the most frequently observed human fetal growth retardation.

Animals↗
PubMed1988

Gyroxin, a toxin from the venom of Crotalus durissus terrificus, is a thrombin-like enzyme.

We report a simple method for the isolation of gyroxin, a protein from the venom of the South American rattlesnake Crotalus durissus terrificus. The intravenous injection of gyroxin into mice produces temporary episodes characterized by opisthotonos and rotations around the long axis of the animal. We found gyroxin to be a glycoprotein with thrombin-like and esterase activities. Gyroxin loses its ability to produce the gyroxin syndrome, its thrombin-like activity and its esterase activity with heat, dithiothreitol, phenylmethylsulfonyl fluoride or diisopropylfluorophosphate. We also report that three other thrombin-like enzymes, crotalase from the eastern diamondback rattlesnake (Crotalus adamanteus), ancrod from the Malayan pit viper (Agkistrodon rhodostoma) and a thrombin-like enzyme from the Central American rattlesnake (Crotalus durissus durissus), produce the gyroxin syndrome in mice. These enzymes may work by releasing neuroactive peptides from endogenous precursors.

Animals↗
PubMed1988

Alexithymia and somatization. A Rorschach study of four psychosomatic groups.

The construct of alexithymia has been postulated as a predisposing factor in psychosomatic illness. The alexithymia construct has achieved wide currency in psychosomatic research and theorizing despite its doubtful psychometric foundations. Also, the question of between-group variability in alexithymia has not been addressed. In this study we proposed and tested a Rorschach measure of alexithymia on four groups of psychosomatic patients (back pain, gastrointestinal, dermatology, migraine headache). It was hypothesized that psychosomatic groups would be more alexithymic than nonpatients. To examine the question of between-group variability in alexithymia, it was hypothesized that back pain patients would be more alexithymic than other psychosomatic groups. Both hypotheses were supported. Additionally, exploratory comparisons between psychosomatic groups revealed a number of differences between the groups in basic personality processes. The findings show promise for the use of the Rorschach test as an alexithymia measure. Based on the current study, heterogeneous grouping of psychosomatic patients in research designs and treatment programs appear to be a highly questionable procedure.

Adult↗
PubMed1987

Umbilical artery flow velocity waveforms and placental resistance: the effects of embolization of the umbilical circulation.

Embolization of the umbilical placental circulation in fetal lambs was carried out to occlude the small vessels of the placental vascular bed and to observe the effect on the umbilical artery flow and flow velocity waveforms. Thirteen singleton fetuses were studied from day 120 of pregnancy. Embolization was achieved by injecting approximately 9 X 10(6) microspheres of 15 micron diameter into the fetal placental cotyledons along the umbilical arteries over 9 days. Umbilical and uterine flows were measured by radioactive microsphere counting. The umbilical placental resistance was increased (0.25 to 0.35 mm Hg.ml.min-1) by embolization, and there was an increase in the umbilical artery systolic/diastolic ratio. Embolization produced a significant fall in umbilical flow expressed either as total flow (312 to 237 ml.min-1) or when normalized by reference against splanchnic flow (3.36 to 1.53). We conclude that the umbilical artery flow velocity waveform systolic/diastolic ratio measures the reflection coefficient at the peripheral vascular bed (the "resistance vessels") of the placenta.

Animals↗
PubMed1987

Randomised controlled trial of lymphoblastoid interferon for chronic active hepatitis B.

Thirty male patients (27 homosexual) with biopsy proven chronic active hepatitis B were randomised to receive lymphoblastoid interferon (Wellferon) or no treatment. All patients were HBeAg positive and had continuing viral replication. Patients receiving treatment were given a single daily intramuscular injection of interferon for 28 days at a starting dose of 2.5 MU/m2 increasing to a maximum of 7.5 MU/m2/day. Transient side effects of malaise and influenza like symptoms occurred in all patients and resolved rapidly after treatment. Hepatitis B viral replication was suppressed during interferon treatment in all patients but the effect was limited to the period of therapy. After one year there was no appreciable difference in viral markers between the two groups of patients and this treatment schedule appears less effective than the thrice weekly, three month regimes recently reported from other centres.

Adult↗
PubMed1987

Effects of acute and prolonged exposure to heat on regional blood flows in pregnant sheep.

This study deals with fetal growth retardation in heat-exposed sheep, and provides information on mechanisms of acclimation to heat. Radioactive microspheres were used to measure regional capillary blood flows in conscious sheep 80-100 days pregnant, at first in a thermoneutral environment, next after 2.5-6 h exposure to a hot environment of 40 degrees C, 25 mmHg water vapour pressure, and then 7 days and 15-20 days later, after spending 9 h daily in the heat. Maternal blood flow in the placental cotyledons was decreased by the first heat exposure, and remained depressed during the period of periodic heating. Reduction in placental blood flow on the maternal side could be part of the mechanism by which fetal development is retarded in heat-stressed sheep. Acclimation to heat was indicated by a decrease in the rate of rise in rectal temperature during the first 2 h of daily exposure to heat. Concomitantly, there was a progressive increase in the blood flow in extremity skin and nasal mucosa, which are tissues concerned with facilitation of heat loss during acute heat stress. However, in respiratory muscles which are also concerned with heat-loss, there was no further increase in flow after the initial response to to acute heat, indicating that heat acclimation is not due to an increased ability to pant. Blood flow in other tissues such as gut, pancreas and adipose tissue progressively decreased. These changes in blood flow have possible adaptive significance.

Acclimatization↗