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Biomedical subjects

M Prior

Publications and source records attributed to M Prior.

At least 73 records · Page 4Linked to original sources
PubMed1991

Effects of hydrogen sulfide exposure on surface properties of lung surfactant.

Hydrogen sulfide is an irritant and chemical asphyxiant gas that exerts its primary toxic effects on the respiratory and neurological systems. Exposure to hydrogen sulfide above a threshold value of 200-300 ppm is characterized by the sudden onset of hemorrhagic pulmonary edema. The purpose of this study was to determine whether this response is associated with changes in the surface properties of pulmonary surfactant. Bronchoalveolar lavage fluid was retrieved from the lungs of Fischer 344 rats exposed to two concentrations of hydrogen sulfide or fresh air for 4 h. Surface tension-lowering properties were assayed using a captive bubble surface tensiometer. Lung injury was assessed by histopathology and measurements of total protein and lactate dehydrogenase activity in the lavagate. Marked abnormalities in surfactant activity were demonstrated in the lavagates from rats exposed to the highest concentration (300 ppm) of hydrogen sulfide. These involved the properties of adsorption to the air-water interface and surface tension lowering under quasi-static interfacial compression. Exposure to 200 ppm hydrogen sulfide had no effect on minimum surface tension despite a significant increase in protein and lactate dehydrogenase in the lavagate. This would suggest a threshold-type response for the inhibition of surfactant activity by hydrogen sulfide. In vitro studies using normal rat surfactant showed that the abnormalities in surfactant activity were due to inhibitors in the edema fluid and not to a direct effect of sulfide on surfactant. The pathophysiological consequences of increased alveolar surface tension after hydrogen sulfide exposure may need to be considered in the clinical setting.

Adsorption↗
PubMed1991

Temperament and behavior of preterm infants: a six-year follow-up.

To test the commonly held premise that prematurity is a risk factor for problems of behavior and social interaction, as well as cognitive and physical development, temperament and behavior of children born preterm and full-term control subjects were compared at five separate time periods from infancy through early school age. All the preterm infants (n = 126) of a representative group of infants enrolled in a longitudinal study (n = 2443) were surveyed at 4 to 8 months corrected age. Subsamples of the group were studied further in successive years as young toddlers (n = 65), older toddlers (n = 60), preschoolers (n = 84), and at early school age (n = 81). At each period there were no differences between those studied and those not studied on socioeconomic status, gestational age, sex, or birth order. Parental ratings of temperament and behavior were used at appropriate ages: the Revised Infant Temperament Questionnaire, the Toddler Temperament Scale, the Childhood Temperament Questionnaire, Behaviour Checklist, Preschool Behaviour Questionnaire, and Rutter's Childhood Behaviour Questionnaire (CBQ), as well as mother's overall rating of temperament. In infancy there were no significant differences on temperament dimensions, clinical temperament categories, or parental ratings of individual or composite behaviors between the preterm and full-term groups. For toddlers, temperament scores were similar for the two groups but preterm subjects were significantly more likely (P less than .01) to have an easy temperament and less likely to have a difficult temperament. There were no differences on any of the other temperament or behavior ratings.(ABSTRACT TRUNCATED AT 250 WORDS)

Child Behavior↗
PubMed1990

Assessment of musical processing in brain-damaged patients: implications for laterality of music.

Reception and production aspects of musical ability were assessed in two studies of left cerebro-vascular accident (LCVA) and right cerebro-vascular accident (RCVA) patients and controls. Musical tasks included perception of rhythm and pitch variations in familiar and unfamiliar tunes; and production of a well-known song, three original melodies, and imitation of rhythm patterns. The only "laterality of music" effect to emerge in the first study was impaired ability in LVCA patients to correctly perceive rhythmic changes. In the second study LCVAs were poorer than the other two groups in the singing of novel melodies, and both lesioned groups were poorer than controls in singing a familiar tune and in tapping rhythms. Premorbid musical ability was significantly related to performance over all groups combined. The RCVA group showed an inconsistent pattern of performance. The LCVA group was consistently more impaired over all tasks but apart from the aforementioned effects this was nonsignificant. It is argued that laterality effects for music processing cannot be reliably established.

Aged↗
PubMed1990

Autistic children's knowledge of thinking and feeling states in other people.

Autistic children, pair matched on chronological and verbal mental age with control children, were given Hobson's task of recognition of emotions and Baron-Cohen's False Belief tasks to assess the replicability of their findings of deficits in understanding of feeling and mental states in autism. There were no group differences on the emotion tasks and performance was related to chronological and verbal mental age. An autism specific deficit was shown in only one of the false belief conditions and again performance was related to verbal comprehension ability. There was some consistency within the group in responses across the two kinds of tasks. Parent reported social behaviour and experience in the autistic children was only weakly related to the ability to pass the tasks. It is argued that the results reflect developmental factors and that claims for an autism specific problem in these kinds of social/cognitive processing may need further exploration.

Adolescent↗
PubMed1990

Capsaicin pretreatment modifies hydrogen sulphide-induced pulmonary injury in rats.

One of the major target organs of hydrogen sulphide gas is the lung. Exfoliation of upper respiratory epithelia and pulmonary edema are prominent effects. Various neuropeptides contained in afferent C-fibres are intimately associated with the epithelia of the conducting airways and are liberated upon exposure to noxious gases. We sought to determine their role in the pathogenesis of hydrogen-sulphide-induced pulmonary injury by pretreating rats with the neurotoxin, capsaicin, which is known to ablate a subpopulation of vagal afferent C-fibres. Groups of capsaicin and saline (control) pretreated Fischer 344 rats were exposed to an edemogenic concentration of hydrogen sulphide (525-559 mg/m3) for 4 hr. Mortality was significantly greater (p less than 0.01) in the capsaicin treated rats (12/12) compared to the control animals (2/12). Pulmonary injury was also more severe in the capsaicin pretreated animals as assessed by lung water content, histological grade of pulmonary edema and protein in the broncho-alveolar fluid. Animals depleted of substance P exhibited a significantly greater (p less than 0.01) degree of bronchial epithelial cell exfoliation and ulceration following exposure to hydrogen sulphide. These experiments indicate that capsaicin sensitive sensory nerves may play a major role in pulmonary defense against the effects of inhaled toxic gases such as hydrogen sulphide.

Animals↗
PubMed1990

Assessment of temperament in the toddler age group.

We used the Toddler Temperament Scale with large representative samples of younger (mean age = 20.5 months; N = 1188) and older (mean age = 35.4 months; N = 1360) Australian toddlers. There were significant sex differences on 6 of the temperament dimensions for the young group, and on 5 of the 9 dimensions for the older group. Older boys were also more likely to be categorized clinically as having a "difficult" temperament and less likely to have an "easy" temperament. Each group was divided into quartiles according to socioeconomic status. For the younger toddlers there were significant differences in 3 of 9 temperament dimensions, and for the older group there were significant differences in 7 of 9 dimensions. Groups with higher socioeconomic status had temperament ratings which were more likely to make them easier to manage, and to be categorized clinically as having an easy temperament, but toddlers with low socioeconomic status were more likely to have a difficult temperament. There were significant differences in temperament dimension scores between Australian toddlers and those studied in an American setting. These results indicate that toddler temperament ratings differ according to age, sex, social class, and cultural context. Great caution needs to be taken in interpreting individual temperament profiles utilizing comparison data obtained from different sociocultural settings. Future temperament "norms" may need to specify characteristics of the group of children from which they were derived to allow more valid comparisons.

Age Factors↗
PubMed1989

Serum levels of soluble interleukin-2 receptor in hairy cell leukaemia: a reliable marker of neoplastic bulk.

In hairy cell leukaemia (HCL), the strong membrane expression of the Tac antigen, corresponding to the p55 chain of the interleukin-2 receptor (IL-2R), is associated with the presence in the serum of high levels of a soluble form of the same molecule (sIL-2R). Previous observations that therapy-induced clinical and haematologic improvement in HCL is accompanied by a progressive decrease of sIL-2R suggest a possible correlation between sIL-2R levels and tumour burden. To verify this hypothesis, we monitored the variation of sIL-2R values in 13 non-splenectomized HCL patients admitted for treatment with recombinant interferon alpha-2. The data were correlated with the estimated weight of bone marrow (BM) and spleen infiltration, which in these patients almost entirely account for the tumour mass. The regression analysis test showed a direct correlation between sIL-2R values and both BM neoplastic involvement (r = 0.63) and spleen tumour mass (r = 0.76). In addition, the correlation was further improved (r = 0.86) when sIL-2R values were correlated with the total neoplastic mass, as calculated by the sum of spleen and BM neoplastic tissue weight. These data indicate that the detection of sIL-2R in HCL is a reliable non-invasive marker of tumour burden, which can be regarded as an additional useful tool for monitoring treatment response.

Adult↗
PubMed1989

Child behavior ratings: the influence of maternal characteristics and child temperament.

This study investigated the extent to which maternal characteristics, such as psychological health problems, marital adjustment and confidence in mother/wife roles, influenced how mothers rated the behavior of their first-born children (n = 100) on the Pre-school Behavior Questionnaire. Results showed that these characteristics were powerful predictors of behavior ratings. In contrast, the independent contribution of child temperament ratings was relatively small. It was concluded that child behavior problem and temperament measures may be confounded. Maternal ratings constitute a valuable source of information concerning parent-child interaction which deserve further investigation, especially of their influence on generally accepted measures of child behavioral adjustment.

Adaptation, Psychological↗
PubMed1988

Urinary MHPG, platelet 3H-imipramine binding and symptomatology in depression: an exploratory study of clinical heterogeneity.

Urinary MHPG concentrations and platelet 3H-imipramine binding (Bmax, Kd) were measured in 20 psychiatric inpatients with diagnoses of major depressive disorder. Clinical assessments were performed using the Present State Examination (PSE) interview, and several dimensions of symptomatology were constructed on the basis of the PSE items. There was a significant positive relationship between Bmax and items reflecting both psychomotor retardation and anxiety. Urinary MHPG bore a comparatively complex nonlinear relationship to Bmax and to the psychomotor retardation symptom dimension. Urinary MHPG also showed an inverse, curvilinear correlation with certain neurotic symptoms. The implications of these findings are briefly discussed in the light of the "dysregulation" hypothesis of affective disorder.

Adult↗
PubMed1988

Processing of timbre and rhythm in musicians and non-musicians.

Expert musicians and non-musicians of similar educational and social class background were compared in two experiments involving perception of timbre and rhythm. In Experiment 1 where dichotic monitoring for the sound of the violin was required, there was a practice effect but no ear or group differences. The rhythm monitoring experiment produced a group by ear interaction with musicians faster on the right ear than the left and faster than non-musicians on the right ear only. Analysis of strategies reported by subjects showed that verbal labelling did not apparently influence laterality. Lack of evidence for individual laterality effects reinforces the claim that with stringent experimental and subject controls there is minimal evidence for musicians non-musician laterality effects.

Adolescent↗
PubMed1988

Temperament in Australian toddlers.

A revised validated version of the Toddler Temperament Scale (TTS) was used to develop normative data for temperament in Australian toddlers. Results confirm the accepted practice of dividing the group into younger and older toddlers, with normative data reported for those younger and older than 24 months. The TTS can be used above the normal cut-off age of 36 months. Care must be taken with interpretation of temperament scores, especially when comparing children of different backgrounds.

Australia↗
PubMed1988

Histologic and ultrastructural alterations in lungs of rats exposed to sub-lethal concentrations of hydrogen sulfide.

Fischer-344 rats were killed 1, 18, and 42 hr after a single 4-hr exposure to an atmosphere of 0, 116, or 615 mg m-3 of hydrogen sulfide (H2S). Lungs, fixed by the intratracheal route, were examined by light and electron microscopy. Histologic changes were transient and mainly present in rats exposed to 615 mg m-3 H2S. Lesions included severe but transitory pulmonary edema and fibrinocellular alveolitis which was restricted to the proximal alveolar region of the lung. Electron microscopically, ciliated bronchiolar cells were the only cells that developed necrosis; they were rapidly replaced by mitosis. Alveolar endothelium had cytoplasmic blebs, but alveolar epithelium had minor changes. No mast cell degranulation was detected in lungs with edema. A 4-hr exposure to 615 mg m-3 is markedly edematogenic for the lung but only moderately cytotoxic for pulmonary cells.

Animals↗
PubMed1988

Origin of the soluble interleukin-2 receptor in the serum of patients with hairy cell leukemia.

High levels of soluble IL-2 receptor (sIL-2R) are detectable in the serum of HCL patients. To determine the cell source of this molecule, we evaluated the presence of sIL-2R in the supernatants obtained from in vitro cultures of leukemic (hairy cell, HC) and non-leukemic lymphocytes from six untreated HCL patients and from an additional four patients under therapy with rIFN-alpha 2. We demonstrated that cultured HCs at resting conditions were able to spontaneously release the sIL-2R, whereas control enriched B cells did not. This phenomenon was present only when culturing HCs recovered from patients observed at the time of diagnosis but was not observed during treatment with rIFN-alpha 2. Following activation in vitro with a series of different stimulatory agents including BCGF, phorbol myristate acetate, and anti-human IgM antibody, cultured HCs increased their capability to shed the IL-2R molecules. On the other hand, the release of sIL-2R from enriched T cell populations from HCL patients did not significantly differ from the value obtained in controls. Taken together, these findings provide evidence that leukemic B cells represent the main source of sIL-2R in HCL patients and further emphasize the importance of evaluating this parameter as a relevant marker for monitoring the effectiveness of rIFN-alpha 2 therapy.

Adult↗
PubMed1988

Nasal lesions in rats exposed to hydrogen sulfide for four hours.

Fischer-344 rats were exposed for 4 hours to 0, 14, 280, or 560 mg of hydrogen sulfide.m-3 and killed 1, 18, or 44 hours later. We evaluated the nasal epithelial cells and determined the anatomic distribution of lesions. Inhalation of 560 mg of hydrogen sulfide.m-3 induced necrosis and exfoliation of respiratory and olfactory mucosal cells, but not squamous epithelial cells. The anatomic distribution of lesions was midway along the nasal passages involving nasal and maxillary conchae, but not ethmoidal conchae. Injured respiratory mucosa repaired rapidly, whereas olfactory mucosa continued to exfoliate at 44 hours after exposure.

Animals↗
PubMed1987

Biochemical and cytologic alterations in the respiratory tract of rats exposed for 4 hours to hydrogen sulfide.

Fischer-344 rats were killed by exsanguination 1, 20, and 44 hr after a single 4-hr exposure to an atmosphere of 0, 10, 200, and 400 ppm of hydrogen sulfide (H2S). Alterations in the activities of lactate dehydrogenase and alkaline phosphatase, and cytomorphology of epithelial cells in fluids obtained by nasal and bronchoalveolar lavage were used as indicators of cell injury. Changes in the number of leukocytes were used as indicators of inflammatory response, and changes in the concentration of protein were used as indicators of altered vascular permeability. Inhalation of H2S resulted in 139, 483, and 817% increased cellularity in the nasal cavity of rats exposed to 10, 200, and 400 ppm, respectively. This was due to marked exfoliation of degenerated epithelial cells and exudation of neutrophils. The high dose of H2S resulted in a moderate increase in lactate dehydrogenase and protein in nasal passages; values returned to baseline levels 20 hr later. Bronchoalveolar cell counts were decreased in rats exposed to 400 ppm and unchanged in those exposed to 10 and 200 ppm. Enzymatic activities in lung lavage fluid were moderately elevated (up to 90%), yet protein concentrations were increased by more than 3000% and remained significantly elevated up to 44 hr after exposure to 400 ppm. It was concluded that inhalation of H2S has a severe cytotoxic effect on the nasal epithelium and a severe edematogenic effect on lung parenchyma. These results are in agreement with autopsy findings of individuals killed by accidental exposure to H2S-containing sour gas.

Alkaline Phosphatase↗