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Biomedical subjects

M Hines

Publications and source records attributed to M Hines.

At least 19 recordsLinked to original sources
PubMed2001

Startle response during smoking and 24 h after withdrawal predicts successful smoking cessation.

RATIONALE: The startle response is thought to reflect changes in attentional processes in humans. The startle response shows a number of forms of plasticity, of which prepulse inhibition (PPI) refers to the attenuation of the startle response to a strong sensory stimulus (pulse), when such a pulse is preceded by a stimulus of lower intensity (prepulse). Recent studies have shown that nicotine modulates startle and PPI of the startle reflex in humans and animals. The present study examined individual differences in cognitive benefits obtained from smoking as indexed by startle response and PPI. OBJECTIVES: We investigated, using a within-subjects design, the effects of cigarette smoking via a comparison of baseline and withdrawal measures of startle and PPI in 18 subjects wishing to quit cigarette smoking. The relapse of five of these subjects enabled a between-group comparison of these measures with the successful quitters. METHODS: Startle and PPI were measured on three separate occasions: before quitting, 24 h after quitting and 1 month after quitting. RESULTS: The presence of a high startle response amplitude while subjects were still engaged in their normal smoking patterns (baseline) and the occurrence of a significant drop of startle amplitude in withdrawal relative to baseline factors were found to be predictive of an individual's ability to quit smoking. Changes in PPI were found to reflect these changes in startle amplitude. CONCLUSIONS: The observed response patterns are discussed in terms of individual differences in commitment to quitting and self-dosing to manipulate attentional mechanisms as measured by the acoustic startle response. Furthermore, it is suggested that these specific response profiles may be predictive of the ability to quit smoking.

Adult↗
PubMed2001

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host for Sarcocystis neurona.

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host of at least three species of Sarcocystis, Sarcocystis dasypi, Sarcocystis diminuta, and an unidentified species; however, life cycles of these species have not been determined. Following feeding of armadillo muscles containing sarcocysts to the Virginia opossum (Didelphis virginiana), the opossums shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.0x7.5 microm and each contained four sporozoites and a residual body. Sporocysts were identified as Sarcocystis neurona using PCR and DNA sequencing. A 2-month-old foal that was negative for S. neurona antibodies in the CSF was orally inoculated with 5x10(5) sporocysts. At 4 weeks post-infection, the foal had a 'low positive' result by immunoblot for CSF antibodies to S. neurona and by week 6 had a 'strong positive' CSF result and developed an abnormal gait with proprioceptive deficits and ataxia in all four limbs. Based on the results of this study, the nine-banded armadillo is an intermediate host of S. neurona.

Animals↗
PubMed2001

The striped skunk (Mephitis mephitis) is an intermediate host for Sarcocystis neurona.

Striped skunks, initially negative for antibodies to Sarcocystis neurona, formed sarcocysts in skeletal muscles after inoculation with S. neurona sporocysts collected from a naturally infected Virginia opossum (Didelphis virginiana). Skunks developed antibodies to S. neurona by immunoblot and muscles containing sarcocysts were fed to laboratory-reared opossums which then shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.0 x 7.5 microm and each contained four sporozoites and a residuum. Sarcocysts from skunks and sporocysts from opossums fed infected skunk muscle were identified as S. neurona using PCR and DNA sequence analysis. A 2-month-old, S. neurona-naive pony foal was orally inoculated with 5 x 10(5) sporocysts. Commercial immunoblot for antibodies to S. neurona performed using CSF collected from the inoculated pony was low positive at 4 weeks p.i., positive at 6 weeks p.i., and strong positive at 8 weeks p.i. Gamma-interferon gene knockout mice inoculated with skunk/opossum derived sporocysts developed serum antibodies to S. neurona and clinical neurologic disease. Merozoites of S. neurona present in the lung, cerebrum, and cerebellum of mice were detected by immunohistochemistry using polyclonal antibodies to S. neurona. Based on the results of this study, the striped skunk is an intermediate host of S. neurona.

Animals↗
PubMed2001

The relationship between prepulse detection and prepulse inhibition of the acoustic startle reflex.

Prepulse inhibition (PPI) of the startle reflex is defined as the attenuation of the startle response to a startling stimulus (pulse), when such a stimulus is briefly preceded by a stimulus of subthreshold intensity (prepulse). PPI is thought to be neither learned nor due to conscious response inhibition, as it occurs at stimulus onset asynchronies (SOAs) too short to enable the activation of a volitional response. The present study explored the latter of these assertions by investigating (a) the degree to which human subjects are able to detect prepulses at SOAs of 30, 60 and 120 ms, and (b) whether such detection is related to inhibition. Startle eyeblink reflex and detection were measured in 39 participants subjected to an acoustic startle paradigm. Results revealed a significant trend in prepulse detection according to SOA, with highest detection rates at the 120-ms SOA (75%). However, trials on which detection occurred did not differ from trials without detection on measures of startle inhibition. This suggests that PPI is independent of awareness of the prepulse.

Acoustic Stimulation↗
PubMed2000

The role of brothers and sisters in the gender development of preschool children.

The study examined whether the sex of older siblings influences the gender role development of younger brothers and sisters of age 3 years. Data on the Pre-School Activities Inventory, a measure of gender role behavior that discriminates within as well as between the sexes, were obtained in a general population study for 527 girls and 582 boys with an older sister, 500 girls and 561 boys with an older brother, and 1665 singleton girls and 1707 singleton boys. It was found that boys with older brothers and girls with older sisters were more sex-typed than same-sex singletons who, in turn, were more sex-typed than children with other-sex siblings. Having an older brother was associated with more masculine and less feminine behavior in both boys and girls, whereas boys with older sisters were more feminine but not less masculine and girls with older sisters were less masculine but not more feminine.

Birth Order↗
PubMed2000

Language lateralization and handedness in women prenatally exposed to diethylstilbestrol (DES).

Hand preferences and language lateralization were assessed in women exposed prenatally to the synthetic estrogen, diethylstilbestrol (DES), and in their unexposed sisters. The DES-exposed women showed an increased degree of hand preference (regardless of direction) and were more likely to be left handed for writing. However, the groups did not differ significantly on a dichotic listening measure of language lateralization. Perhaps as a result of the alterations in hand preferences, the typical relationship between hand preferences and language lateralization was disrupted in the DES-exposed group. Also, within the DES-exposed group, exposure early in gestation correlated with left handedness whereas exposure late in gestation correlated with reduced left ear (right hemisphere) scores on the verbal dichotic task. Results are discussed in terms of theoretical perspectives predicting hormonal influences on sexual differentiation of hemispheric asymmetry and in terms of separate critical periods for hormonal effects on individual sexually differentiated characteristics.

Adolescent↗
PubMed2000

Prophylactic nitroglycerin did not reduce myocardial ischemia during accelerated recovery management of coronary artery bypass graft surgery patients.

OBJECTIVE: To evaluate the use of a high dose of nitroglycerin (NTG) for prophylaxis against myocardial ischemia and infarction in patients undergoing coronary artery bypass graft (CABG) surgery with accelerated recovery. DESIGN: Prospective, double-blind, placebo-controlled randomized study. SETTING: A university-based medical center. PARTICIPANTS: Forty adult patients presenting for elective CABG surgery. INTERVENTIONS: Forty patients were divided into 2 blinded study groups. Twenty patients received 2 microg/kg/min of NTG starting before induction of anesthesia and continuing for 6 hours after extubation in the intensive care unit. The placebo group (n = 20) received normal saline during this same interval. MEASUREMENTS AND MAIN RESULTS: Hemodynamics, incidence and severity of myocardial ischemia, and myocardial infarction rates were determined. There were no differences in hemodynamic parameters between groups. The incidence of ischemia was approximately 35% in each group. Myocardial infarction (as determined by elevated creatine kinase-MB fraction, troponin I, and electrocardiogram criteria) was 10% in the placebo group and 5% in the NTG group (p = 0.234). CONCLUSIONS: This study shows a high incidence of myocardial ischemia and infarction in patients presenting for CABG surgery with an accelerated recovery management scheme. NTG was well tolerated clinically; however, it was not found to be protective against myocardial ischemia or infarction in this setting.

Adult↗
PubMed2000

The durability of endovascular treatment of multisegment iliac occlusive disease.

PURPOSE: The effectiveness of endovascular treatment of multisegment iliac occlusive disease (involving two or more common and/or external iliac arteries) was determined. METHODS: All patients who underwent angioplasty or stenting of at least two separate iliac artery segments were identified. Demographic data were recorded. Technical success, hemodynamic success, and aortoiliac primary and primary-assisted patency were analyzed by using the Society for Vascular Surgery and International Society for Cardiovascular Surgery (SVS/ISCVS) criteria. Multivariate, life table analysis was used as a means of determining outcome predictors. RESULTS: Eighty-seven patients underwent 207 iliac artery angioplasties and 115 iliac artery stents, which were performed in 210 iliac segments for disabling claudication in 60% of cases, for rest pain in 17% of cases, and for tissue loss in 23% of cases. Two iliac segments were treated in 64% of patients, three segments were treated in 28% of patients, and four segments were treated in 8% of patients. The complication rate was 11%. Initial hemodynamic success was achieved in 72% of cases. Clinical improvement occurred in 88% of patients. Subsequent endovascular reintervention was required in 29% of patients, whereas surgical inflow procedures were required in 14% of patients to maintain aortoiliac patency. The mean time from the primary intervention to the first reintervention was 10 +/- 3 months. At 6, 12, and 36 months after intervention, the primary patency rates of the aortoiliac segment were 76%, 61%, and 43%, respectively, and the primary assisted patency rates were 95%, 87%, and 72%, respectively. Only the presence of an external iliac artery stenosis adversely affected both primary and assisted-primary patency. At 6, 12, and 36 months, the aortoiliac primary patency rates in patients without the presence of an external iliac artery stenosis were 88%, 78%, and 69%, respectively, compared with 68%, 47%, and 18%, respectively, in patients with external iliac artery lesions (P <. 0001). CONCLUSION: Endovascular therapy for multisegment aortoiliac occlusive disease has acceptable patency rates; however, reintervention is often needed. The presence of external iliac artery disease is a significant predictor of poor outcome.

Angioplasty, Balloon↗
PubMed2000

Mushroom toxicity in a horse with meningioangiomatosis.

We describe a fatal case of mushroom intoxication in an 18-y-o horse presumably due to Amanita verna. Horses are normally regarded as too fastidious to eat the ill-flavored toadstools. In this case, the horse had a rare benign brain tumor, meningioangiomatosis, which may have altered the horse's normal eating behavior resulting in consumption of the mushrooms.

Amanita↗
PubMed1999

162 cases of aldicarb intoxication in Georgia domestic animals from 1988-1998.

A 10-y retrospective study of aldicarb intoxication in domestic animals from 1988 to 1998 is provided from animals submitted to the University of Georgia Veterinary Diagnostic and Investigational Laboratory. Within the period examined, 162 separate cases were confirmed and 18 additional cases were suspected based on bioassay but could not be confirmed. Some cases involving as many as 15 affected animals. Dogs were most often involved, but cats, horses, cattle and goats were also poisoned. Most intoxications appeared intentional or malicious. "Baits" including frankfurters, ham or ground beef were consistently found in stomach contents. The restriction of aldicarb to an agricultural soil application limits accidental exposure to domestic animals. Its use is regulated through license in Georgia as a systemic insecticide for pecan trees, peanuts and cotton. Unfortunately, aldicarb seems favored as a malicious poison, possibly due to its quick lethality.

Aldicarb↗
PubMed1998

Androgen-behavior correlations in hypogonadal men and eugonadal men. II. Cognitive abilities.

Sex-typed cognitive abilities were assessed in 33 hypogonadal men receiving testosterone replacement therapy, 10 eugonadal men receiving testosterone in a male contraceptive clinical trial, and 19 eugonadal men not administered testosterone. Prior to and following hormone administration, men completed four tests measuring visuospatial ability, three tests measuring verbal fluency, two tests measuring perceptual speed, and a measure of verbal memory. Group differences in testosterone levels were unrelated to performance on most cognitive measures, including visuospatial ability. Relative to other men, hypogonadal men were impaired in their verbal fluency and showed improved verbal fluency following treatment with testosterone. These data suggest that testosterone may enhance verbal fluency in hypogonadal men and support the general hypothesis that current levels of testosterone may influence some aspects of cognitive function.

Adult↗
PubMed1998

Estrogen and memory in a transsexual population.

The association between administered estrogen and performance on verbal memory and other cognitive tasks was examined. Male-to-female transsexuals undergoing estrogen treatment for sex reassignment (n = 29) scored higher on Paired Associate Learning (PAL) compared to a similar transsexual control group, awaiting estrogen treatment (n = 30) (P < 0.05). No differences between groups receiving and not receiving estrogen were detected on a control memory task (Digit Span) or on other cognitive tasks including Mental Rotations and Controlled Associations. There were no group differences in age. Group differences in mood or in general intellectual ability also did not explain the findings. Results suggest a specific influence of estrogen in men on verbal memory tasks, similar to that seen in prior studies of women. They are discussed in terms of differential processing demands of the two memory tasks and possible differences between estrogenic influences on Mental Rotations and Controlled Associations in men versus women.

Adult↗
PubMed1998

Abnormal sexual development and psychosexual issues.

Animal models of gonadal hormone influences on the sexual differentiation of brain and behaviour are reviewed and discussed as a basis for predicting hormonal influences on human neurobehavioural development. Behavioural outcomes in clinical intersex cases, including congenital adrenal hyperplasia, androgen insensitivity syndrome, enzymatic deficiencies and situations in which hormones have been prescribed during pregnancy are reviewed. It is concluded that the prenatal or neonatal hormone environment contributes to the development of human behaviours that show sex differences, particularly childhood play behaviour, sexual orientation and core gender identity. There also is some evidence for influences on aggression and cognition. It is also concluded that additional research is needed to determine why some intersex patients assigned and reared as girls are not successful in this identity and role.

Adrenal Hyperplasia, Congenital↗
PubMed1998

Effects of cardiopulmonary bypass and deep hypothermic circulatory arrest on the thyroid axis during and after repair of congenital heart defects: preservation by deep hypothermia?

UNLABELLED: Thyroid function is altered by cardiopulmonary bypass (CPB) in children. To better understand the cause of altered thyroid hormone levels, we compared the effects on the pituitary-thyroid axis of CPB in 23 children undergoing elective repair of congenital heart defects. Twelve patients underwent CPB with moderate hypothermia without a period of deep hypothermic circulatory arrest (DHCA), and eleven underwent CPB with DHCA. Nine blood samples were collected from each patient before, during, and after CPB. Free T3 (FT3), free T4 (FT4), total T3 (TT3), total T4 (TT4), thyrotropin (TSH), and albumin were measured; concentrations of each decreased significantly with the onset of CPB (P < 0.05). There was a greater decline in hormone than in albumin concentrations, which suggests that factors in addition to hemodilution were present (P < 0.05). TSH concentrations in the DHCA group began to increase during cooling, exceeding baseline values after rewarming and after separation from CPB. Patients undergoing CPB without DHCA had persistently low TSH concentrations (P < 0.05). By Postoperative Days 1 and 2, TSH concentrations in both groups were similar and significantly lower than baseline values (P < 0.001). FT3, FT4, TT3, TT4, and albumin all increased during CPB after an initial decrease. Of these, only albumin and FT4 recovered to their baseline values after the initial decrease. Nevertheless, by Postoperative Day 1, both groups demonstrated the "sick" euthyroid syndrome and could not be distinguished from one another. This study demonstrates greater pituitary release of TSH in children undergoing repair of congenital heart defects with DHCA compared with CPB alone, the cause of which could not be determined in this study. However, despite the increase in TSH in the DHCA group, the thyroid hormone concentrations failed to increase appropriately. IMPLICATIONS: Early after deep hypothermia circulatory arrest, thyrotopin concentrations increase appropriately, responding to decreased concentrations of T3; however, all children undergoing cardiopulmonary bypass eventually develop a "sick" euthyroid syndrome by Postoperative Day 1. Whether this difference represents better protection of neuroendocrine function by deep hypothermic circulatory arrest (relative to cardiopulmonary bypass alone) remains speculative.

Cardiopulmonary Bypass↗
PubMed1997

Absent right superior vena cava in visceroatrial situs solitus.

Absence of the right superior vena cava (SVC) in visceroatrial situs solitus is rare (0.07% to 0.13% of congenital cardiovascular malformations), and little is known about the type and frequency of additional heart defects and arrhythmias. We reviewed previous publications and present 9 new cases. Based on 121 known cases, we found that this anomaly is typically characterized by: (1) persistence of the left SVC draining into the right atrium by way of the coronary sinus, and (2) left-sided azygos vein draining into the left SVC. Less constant features were: (3) additional cardiovascular malformations (46%), and (4) rhythm abnormalities (36%) that usually appeared related to the complications of old age. Since absence of the right SVC is clinically silent, its status should be assessed echocardiographically prior to invasive medical or surgical procedures. This is important to avoid various management difficulties during the following procedures: (1) implantation of a transvenous pacemaker, (2) placement of a pulmonary artery catheter for intraoperative or intensive care unit monitoring without fluoroscopy, (3) systemic venous cannulation for extracorporeal membrane oxygenation, (4) systemic venous cannulation for cardiopulmonary bypass, (5) partial or total cavopulmonary anastomoses; and (6) orthotopic heart transplantation and endomyocardial biopsies.

Abnormalities, Multiple↗
PubMed1997

Androgen-behavior correlations in hypogonadal men and eugonadal men. I. Mood and response to auditory sexual stimuli.

Mood and response to auditory sexual stimuli were assessed in 33 hypogonadal men receiving testosterone (T) replacement therapy, 10 eugonadal men receiving T in a male contraceptive clinical trial, and 19 eugonadal men not administered T. Prior to and after 6 weeks of hormone administration, men completed a mood questionnaire, rated sexual arousal to and sexual enjoyment of auditory sexual stimuli, and performed a dichotic listening task measuring selective attention for sexual stimuli. Mood questionnaire results suggest that T has positive effects on mood in hypogonadal men when hormone levels are well below the normal male range of values, but does not have any effects on mood when hormone levels are within or above the normal range. However, increased sexual arousal and sexual enjoyment were associated with T administration regardless of gonadal status. Eugonadal men administered T also increased in the bias to attend to sexual stimuli. In contrast, the comparison group of eugonadal men not administered T showed no mood or sexual behavior changes across the two test sessions. These data support a positive relationship between T and sexual interest, sexual arousal, and sexual enjoyment in men.

Administration, Sublingual↗
PubMed1996

Sexual differentiation of cognitive abilities in women exposed to diethylstilbestrol (DES) prenatally.

In nonhuman animals, prenatal exposure to androgens or estrogens enhances development of male-typical characteristics (masculinizes) and impairs development of female-typical characteristics (defeminizes). We investigated the hypothesis that prenatal exposure to the synthetic estrogen, diethylstilbestrol (DES), similarly masculinizes or defeminizes cognitive development in women. Forty-two DES-exposed women and 26 of their unexposed sisters were studied. No group differences were seen for abilities at which females excel on average (verbal fluency, perceptual speed and accuracy, and associative memory), for abilities at which males excel on average (visuospatial abilities), or for abilities that do not show sex differences (vocabulary, nonverbal intelligence). The time of prenatal exposure to DES correlated with visuospatial performance with later exposure associated with better performance. However, the subgroup of women exposed to DES late in gestation did not differ from unexposed women on these measures. Results support the conclusion that prenatal exposure to DES has little or no influence on cognitive development in women. However, they do not preclude other types of early hormonal influences on human cognition, such as prenatal influences of androgen or influences of androgens or estrogens during the early postnatal period.

Adult↗