Biomedical subjects

M A Barnes

Publications and source records attributed to M A Barnes.

11 recordsLinked to original sources

PubMed1992

Reading in children and adolescents after early onset hydrocephalus and in normally developing age peers: phonological analysis, word recognition, word comprehension, and passage comprehension skill.

Compared 50 children with early hydrocephalus, tested between the ages of 6 and 15 years, and their 51 age- and education-matched controls on 4 reading skills. Hydrocephalus and control groups did not differ in the ability to recognize words or to use phonological skills to decode "pretend" words, although the hydrocephalus group was poorer than the controls in understanding real words and texts. When individual differences in word recognition ability were controlled, the hydrocephalus group remained poorer than the controls in understanding single words and passages of text. Word recognition and passage comprehension skills were more highly correlated in the control group than in the hydrocephalus group. The passage comprehension scores of the hydrocephalus group lagged behind their word recognition scores, even for those children of normal or better IQ. Although the factors related to proficient and deficient reading comprehension for children with early hydrocephalus require further study, the present data show that adequate levels of word recognition, at least as measured by accuracy, in these children coexist with a significant deficit in reading comprehension.

Adolescent↗

PubMed1991

Exogenous opioids increase plasma prolactin in Holstein calves primarily via a dopaminergic mechanism.

A study was conducted to determine whether exogenous opioids increase prolactin (PRL) secretion in Holstein heifer calves via a dopaminergic mechanism. Twenty-four Holstein heifer calves ranging in age from 5 to 7 mo were assigned to one of four treatment groups (six/treatment): 1) injection of saline (SAL); 2) injection of a synthetic enkephalin (D-Ala2, N-Me-Phe4, Met(O)5-ol enkephalin; DAMME); 3) injection of DAMME after pretreatment with the long-acting dopamine agonist 2-bromo-alpha-ergocryptine; or 4) injection of thyrotropin-releasing hormone (TRH) after pretreatment with 2-bromo-alpha-ergocryptine. Calves were equipped with indwelling jugular cannulas on d 1, and baseline plasma PRL concentrations were established. Animals receiving 2-bromo-alpha-ergocryptine were injected s.c. 3 h after the last baseline sample was drawn on d 1. On d 2, calves assigned to receive SAL, DAMME, or TRH were injected 2 h after the start of sampling, and sampling was continued for an additional 4.5 h. Basal plasma PRL was lower (P less than .01) on d 2 in calves injected with 2-bromo-alpha-ergocryptine than baseline levels on d 1. Plasma PRL was higher (P less than .01) in calves not pretreated with 2-bromo-alpha-ergocryptine after DAMME injection on d 2 but was not different after DAMME injection in calves pretreated with 2-bromo-alpha-ergocryptine. In contrast, plasma PRL increased (P less than .01) after TRH injection on d 2 in calves pretreated with 2-bromo-alpha-ergocryptine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Knowing the meaning, getting the point, bridging the gap, and carrying the message: aspects of discourse following closed head injury in childhood and adolescence.

Pragmatic communication or discourse was studied in 33 children and adolescents following closed head injury. Three-quarters of the sample was impaired on at least one of four discourse tests (knowing the alternate meanings of ambiguous words in context; getting the point of figurative or metaphoric expressions; bridging the inferential gaps between events in stereotyped social situations; and producing speech acts that express the apparent intentions of others). Resolution of ambiguity was correlated with word fluency and verbal domain knowledge, but not with object naming; understanding of metaphor was correlated with verbal domain knowledge, but not with literal sentence comprehension or with the formation of analogies; making inferences was correlated with working memory capacity but not with social knowledge; and producing speech acts was not correlated either with sentence construction or with social knowledge. These associations and dissociations reveal some of the correlates of impaired discourse processing after closed head injury in childhood and adolescence, as well as bearing on theoretical questions concerning the nature of normally developing discourse processes.

Adolescent↗

PubMed1990

A part-time Level II fieldwork program.

This paper describes an alternative to the traditional Level II fieldwork program for master's degree students in occupational therapy. In this part-time 9-month program, students complete the fieldwork requirement while simultaneously balancing academic responsibilities. One advantage of this program over the traditional 3-month program is that the extended length of time offers students the opportunity to develop clinical skills beyond the technical level.

Clinical Competence↗

PubMed1989

Response to selection for milk yield and metabolic challenges in primiparous dairy cows.

The effect of selection for milk yield on lactation yield, net energy balance, and on plasma growth hormone, insulin, prolactin, nonesterified fatty acids and glucose was studied in two groups of primiparous Holstein cows of differing genetic merit. Net energy balance was calculated and serial blood samples were collected for a 7 hr period at 0, 45, 90 and 180 days postpartum. Growth hormone releasing factor (.2 microgram/kg BW) was administered after 2.5 hr at 0, 45 and 180 days postpartum, while epinephrine (.7 microgram/kg BW) was administered at 90 days postpartum. Milk yield was greater, net energy balance was decreased and plasma growth hormone was greater in genetically superior selection group cows compared to control cows. Growth hormone showed similar increases in both genetic groups in response to growth hormone releasing factor, while prolactin, insulin and glucose were not altered. Epinephrine stimulated an increase in plasma nonesterified fatty acids, glucose and insulin, but responses did not differ between genetic groups. Results indicate differences exist in production efficiency, net energy balance and plasma growth hormone concentration among dairy cattle as a result of selection for milk yield and suggest that selection pressure may act to alter homeorhetic control of nutrient metabolism.

Animals↗

PubMed1986

Lactogenic hormone receptors in mammary membrane preparations from prepartum and 60 and 180 day post-partum Holstein cattle.

Mammary tissue from nine Holstein cows was collected within 1 week of parturition and at 60 and at 180 days post partum. Blood samples were collected by puncture of the coccygeal vein or artery at 6-h intervals from 2 days before to 2 days after surgery. A membrane-enriched fraction of tissue homogenates was prepared by differential centrifugation. A microcomputer program (LIGAND) provided estimates of the dissociation constant (Kd) and receptor concentrations using Scatchard analysis of competition of radioiodinated human GH by bovine prolactin (NIH-bPRL-6), ovine prolactin (NIH-oPRL-15) and unlabelled human GH (NIH-hGH-I-1). Split-plot analysis of variance of hormone data indicated that mean prolactin concentrations during the periparturient period were greater than those at 60 or 180 days post partum. However, no differences were evident in prolactin content of blood samples collected immediately before biopsy. Analysis of variance of Scatchard data indicated that the Kd of the lactogenic hormone receptor did not differ at different stages of lactation, and averaged 89.7 nmol/l. Receptor concentrations were lower during the prepartum period than at 60 and 180 days post partum (0.65 vs 1.2 and 1.5 fmol/mg membrane protein respectively). The Kd of the lactogenic hormone receptor was similar when estimated with NIH-bPRL-6 or NIH-oPRL-15 competition, but 100-fold greater when estimated with NIH-hGH-I-1. It is concluded that lactogenic hormone receptor concentrations in bovine mammary tissue increase with the onset of lactation, with a pattern similar to that observed in non-ruminants.

Animals↗

PubMed1986

Effect of genetic selection for milk yield and increased milking frequency on plasma growth hormone and prolactin concentration in Holstein cows.

Fifty Holstein cattle, either second to fourth generation daughters of cows randomly bred to non-commercial sires originating in the Virginia Tech dairy herd (estimated mean PDM84 = -455 kg, control animals), or daughters of cows bred to commercially available sires (mean PDM84 = +368 kg, selection animals), were randomly assigned to be milked twice or thrice daily starting at parturition. Serial blood samples were collected via jugular cannulae at 30, 90 and 200 d post-partum (DPP) during both the first and second lactations. Blood samples were collected for 3 h prior to and 4 h following thyrotropin releasing hormone (TRH) administration, and were analyzed for growth hormone (GH) and prolactin (PRL) concentrations. Dry matter intake, body weight and milk yield and fat content were used to calculate net energy balance (NEB) of animals at each DPP sampling period. Mean plasma GH concentrations were greater (P less than .01) in selection vs control animals both before and after TRH administration, and decreased (P less than .01) with advancing lactation (30 greater than 90 greater than 200 DPP). However, NEB was not influenced by genetic merit, implying that observed differences in GH concentrations were not due to that trait. Plasma PRL concentrations were not affected by genetic merit or DPP, but were greater (P less than .01) in the second vs first lactation. Neither PRL or GH concentrations were affected by frequency of milking. The results support the contention that increased plasma GH concentrations are associated with selection for increased milk yield.

Animals↗

PubMed1985

Alternative indications for pulsatile gonadotropin-releasing hormone therapy in infertile women.

Three groups of women with different types of ovulatory dysfunction who had failed to conceive on conventional therapy were treated with pulsatile gonadotropin-releasing hormone (GnRH). Group A consisted of nine patients with luteal phase defect; group B included four patients with apparently normal menstrual cycles but disordered folliculogenesis seen by serial ultrasound examinations; and group C consisted of eight patients who exhibited anovulation or irregular ovulation. GnRH was administered subcutaneously or intravenously in dosages varying from 5 micrograms to 20 micrograms, with pulse frequency of 2 to 3 hours in 53 cycles. Forty-one cycles were ovulatory. Four pregnancies resulted, one ending in miscarriage at 12 weeks' gestation. Our results indicate that GnRH may be used as an alternative to the prevalent therapeutic methods for ovulatory dysfunction. Only those women who had anovulation and abnormal basal levels of serum luteinizing hormone were resistant to GnRH therapy.

Adult↗

PubMed1985

Influence of selection for milk yield on endogenous hormones and metabolites in Holstein heifers and cows.

Plasma concentrations of prolactin (PRL), growth hormone (GH), insulin, glucagon, glucose, urea and free fatty acids (FFA) were measured in Holstein calves, yearlings, bred heifers and primiparous cows, either sired by bulls with high predicted differences (PD) for milk (selection group) or by bulls from an unselected random bred control population (control group; n = 6). Serial blood samples were collected before and after feeding for an 8-h period from 0900 to 1700 h. All animals were fed a complete feed at 1100 h and administered insulin (.6 IU/100 kg body weight) at 1400 h. Mean plasma PRL was greater in control animals after feeding and insulin administration, while GH was greater overall in selection cattle. Insulin remained elevated longer in selection animals after exogenous administration, and plasma glucagon was increased in the control group. While plasma glucose and urea were unaffected by genetic group, plasma FFA were elevated in selection group calves and primiparous cows compared with the control group. All hormones and metabolites differed among the pre- and post-feeding and insulin administration periods and also with age. Mean PRL and GH increased after feeding, while glucagon decreased after exogenous insulin. Plasma FFA declined after feeding, while urea and glucose were similar before and after feeding. Mean PRL increased and glucagon decreased with advancing age and plasma GH and insulin showed inverse relationships at different ages. Plasma FFA changes closely followed GH changes with age, while plasma glucose more closely followed insulin changes with age. Results indicate that all hormones measured and FFA responded to genetic selection for milk, and increases in GH are uniformly associated with increased genetic potential for milk yield.

Animals↗

PubMed1977

The effect of antibiotics on cell-mediated immunity.

Normal human lymphocytes in culture were stimulated by the addition of phytohemagglutinin, and deoxyribonucleic acid (DNA) synthesis was measured by the incorporation of tritiated thymidine. The effect of 11 commonly used antibiotics on DNA synthesis then was measured by adding each antibiotic to the culture in concentrations ranging from 2 to 64 microng/ml, a range which covers the plasma levels obtained during customary clinical therapy. Severe dose-dependent suppression of DNA synthesis was found in the presence of two preparations of minocycline, oxytetracycline, and the ascorbic acid salt of tetracycline. Less severe but stil significant suppression was found in the presence of chloramphenicol, clindamycin, tetracycline, and ascorbic acid alone. No effect was noted when penicillin, carbenicillin, or cephalothin was added, and slight stimulation was found in the presence of gentamicin. It is postulated that these findings may help to explain fungal and viral superinfection following antibiotic therapy and that they may play a role in the failure of antibiotic therapy to eliminate some infections.

Anti-Bacterial Agents↗

PubMed1976

use of F(ab')2 fragment in experimental skin transplantation for burns.

In a series of experiments involving approximately 500 animals, burned rats were administered the F(ab')2 fragment of antidonor IgG to study the survival of incompatible skin allografts. No prolongation was noted when treatment consisted of antidonor F(ab')2 fragment alone. This was true whether the fragment was raised against donor spleen cells of donor skin, whether the skin allograft was partial or full thickness and whether the systemic treatment of the recipients was preceded by a period of incubation of the graft in F(ab')2 fragment or not. Significant prolongation of survival was noted when the fragment was raised against both donor and recipient histocompatibility antigen and when the donor skin was incubated in steroids as well as in F(ab')2 fragment prior to grafting. Additional findings included the confirmation of prolonged allograft survival by increasing burn size and the prolongation of allograft survival by the presence of intact eschar.

Animals↗