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Biomedical subjects

R D Martin

Publications and source records attributed to R D Martin.

At least 37 records · Page 2Linked to original sources
PubMed1998

Evidence from urinary cortisol that maternal behavior is related to stress in gorillas.

By studying western lowland gorillas (Gorilla gorilla gorilla, n = 8) in zoological gardens via ethological and non-invasive physiological techniques, we have demonstrated that their postpartum maternal behavior is related negatively to their postpartum urinary titers of cortisol. On the basis of this finding, it is proposed that postpartum stress contributes to disrupted maternal behavior in the gorilla in captivity. Morning urine samples were collected with a mean sampling interval of 1.6 days from Day 14 prepartum to Day 14 postpartum (n = 11 pregnancies). Creatinine-indexed (Cr) urinary cortisol titers declined significantly between Day 9 to 1 prepartum (0.634 +/- 0.014 microg/mg of Cr, mean +/- SEM) and Day 1 to 6 postpartum (0.396 +/- 0.030 microg/mg of Cr, mean +/- SEM; p < 0.01-0.001). For each pregnancy, the relative postpartum decline in urinary cortisol was calculated as (microg of cortisol/mg of Cr Day 1 to 4)/(microg of cortisol/mg of Cr Day -4 to -1). Values ranged from 0.35 to 1.12, were independent of absolute prepartum cortisol titers, and were interpreted as evidence of inter-female differences in postpartum hypothalamo-pituitary-adrenal axis activity and, therefore, postpartum stress. This postpartum stress index was negatively correlated with the amount of time (0-100%) that females carried and supported their 0-14 day-old infants in a ventral position during locomotion (r(s) = -0.68, p < 0.05) and tended to be negatively correlated with the total amount of time (0-100%) they spent in ventro-ventral contact with their infants (r(s) = -0.58; p < 0.10). This study provides the first physiological evidence that postpartum stress is an important etiologic factor in gorilla maternal failure in captive environments.

Animals↗
PubMed1998

Physiological Responses to parental separation and a strange situation are related to parental care received in juvenile Goeldi's monkeys (Callimico goeldii).

The relationship between parental care received and physiological and behavioral responses to parental separation, isolation, and reunion was investigated in seven juvenile Goeldi's monkey living in their family groups. Physiological responses were measured non-invasively: the hypothalamic-pituitary-adrenal axis via urinary cortisol output and the autonomic nervous system via piloerection on the tail. Parent-infant aggression demonstrated high intergroup variation and predicted: (a) an increase in urinary cortisol output, r(s) = 0.86, p = 0.04, and duration of piloerection, r(s) = 0.71, p = 0.08, at initial separation-isolation; (b) adaptation of piloerection, r(s) = -0.89, p = 0.03, to repeated separation-isolation. Juvenile Goeldi's monkeys that had received high parental aggression were more physiologically responsive to separation; they also sought more contact with their mothers at reunion, rs = 0.93, p = 0.02. We propose that these data are consistent with the hypothesis that high emotional reactivity is related to insecure attachment to aggressive parents in this New world primate.

Animals↗
PubMed1998

A reexamination of the phylogenetic position of Callimico (primates) incorporating new mitochondrial DNA sequence data.

The New World monkeys are divided into two main groups, Callitrichidae and Cebidae. Callimico goeldii shares traits with both the Cebidae and the Callitrichidae. Recent morphological phyletic studies generally place Callimico as the most basal member of the Callitrichidae. In contrast, genetic studies (immunological, restriction fragment, and sequence data) have consistently placed Callimico somewhere within the Callitrichidae, not basal to this clade. A DNA sequence data set from the terminal 236 codons of the mitochondrial ND4 gene and the tRNA(His), tRNA(Ser), and tRNA(Leu) genes was generated to clarify the position of Callimico. The sequences of 887 base pairs were analyzed by maximum-parsimony, neighbor-joining, and maximum-likelihood methods. The results of these various methods are generally congruent and place Callimico within the Callitrichidae between the marmosets (Callithrix and Cebuella) and the tamarins (Saguinus and Leontopithecus). Combined analyses of all suitable nuclear and mitochondrial gene sequences confirm the position of Callimico between the marmosets and the tamarins. As available molecular evidence indicates that Callimico is more closely related to the marmosets than to the tamarins, a reconsideration of the morphological evidence in light of the consensus tree from DNA sequence analyses is warranted. The marmosets and tamarins share four morphological characters (loss of the third molar, loss of the hypocone, reduced body size, reproductive twinning). Dwarfism may have evolved repeatedly among the Callitrichidae. It is well-known that the loss of a character can occur many times independently. The reproduction of marmosets and tamarins is extremely specialized and it is difficult to imagine that this complex and unique twinning system evolved separately in marmosets and tamarins. However, it is possible that a secondary reversal to single offspring took place in Callimico.

Animals↗
PubMed1998

The major histocompatibility complex and mate choice: inbreeding avoidance and selection of good genes.

It has been known for decades that MHC genes play a critical role in the cellular immune response, but only recent research has provided a better understanding of how these molecules might affect mate choice. Original studies in inbred mouse strains revealed that mate choice was influenced by MHC dissimilarity. Detection of MHC differences between individuals in these experiments was related to olfactory cues, primarily in urine. Recent studies in humans have shown an analogous picture of MHC-based mating. Taken together, these findings could support either the hypothesis of MHC-based inbreeding avoidance or the hypothesis of MHC-related avoidance of reproductive failure, since studies in mice, humans and pigtailed macaques have shown that parental sharing of certain MHC alleles correlates with frequent spontaneous abortion or prolonged intergestational intervals. Data from many mammalian species clearly demonstrate that reproductive failure occurs as a result of inbreeding. Therefore, MHC similarity might serve as an indicator of genome-wide relatedness. In contrast, increased fitness due to the presence of individual MHC alleles in a pathogenic environment could explain MHC-based selection of currently good genes. Specifically, the physical condition of long-living animals depends on the ability to respond to immunological challenge and an individual's MHC alleles determine the response, since, unlike the T cell receptors, MHC alleles are not somatically recombined. Therefore, sexual selection of condition-dependent traits during mate choice could be used to select successful MHC alleles, thereby providing offspring with a higher relative immunity in their pathogenic environment.

Animals↗
PubMed1998

Creating a benefit management information database.

In this case study, a real-life information technology conundrum is fictionalized to illustrate the potential benefits of retaining corporate knowledge through the creation of an information repository in a managed health care plan.

Archives↗
PubMed1997

Rate of metabolism in the smallest simian primate, the pygmy marmoset (Cebuella pygmaea).

Rate of metabolism was measured with six adult pygmy marmosets (Cebuella pygmaea) at regulated ambient temperatures ranging between 20 degrees C and 35 degrees C. A novel combined nest box and metabolic chamber was designed to allow nighttime measurements on immobile animals in their home cage without disturbance. The basal rate of metabolism (BMR) was 98 ml O2 h-1, representing 74% of the value expected from the equation of McNab [Quarterly Review of Biology 63:25-54, 1988] relative to body mass. The thermoneutral zone was approximately 27-34 degrees C. Below the lower critical temperature (27-28 degrees C), thermal conductance (12.9 ml O2 h-1 degree C-1) was close to the predicted value. Body temperature ranged between 34.9 degrees C and 35.5 degrees C at night. When two animals rested together overnight in the nest box, the lower critical temperature was slightly lowered, and individual energy expenditure at 20-21 degrees C was reduced by about 34%. The basal rate of metabolism of C. pygmaea is much lower than reported in an earlier study based on daytime measurements but agrees with values reported from a more recent study conducted at night with a classical metabolic chamber. In order to compare the BMR of C. pygmaea with that of other primates, 23 species were included in a comparative study taking into account both phylogeny and body mass (independent contrasts approach). The scaling exponent of BMR to body mass obtained was indistinguishable from that published for eutherian mammals in general. Cebuella and Callithrix exhibit the lowest basal rates known for simians. This trait may possibly be linked to the natural diet, which includes a large proportion of gums that are difficult to digest, but additional metabolic studies on primates are needed for further examination of its adaptive significance.

Animals↗
PubMed1997

Outcomes study of a course in breast-cancer screening.

BACKGROUND: The Breast Cancer Screening Module is a professional training course within the Professional Education for Prevention and Early Detection (PEPED) program at the University of Texas M. D. Anderson Cancer Center. An outcomes study was done to determine the module's ability to improve screening practices crucial to breast-cancer control. METHODS: The five-day course combines 17 hours of class work with 20 hours of hands-on clinical training. Subjects were followed for one year post-training. Six outcome areas were evaluated: 1) knowledge about breast-cancer prevention; 2) clinical skills; 3) changes in routine practice; 4) numbers of patients screened, referred, and diagnosed; 5) trainee satisfaction with the course; and 6) barriers to implementing screening in routine practice. The study population was 63 subjects (all nurse professionals). RESULTS: Outcomes were positive in all six evaluation areas-significant gains in general and clinical knowledge tests (p < or = 0.05); a significant increase from 54.2% pre-training to 70.5% post-training in risk counseling (p < or = 0.05); a sustained increase in screening practices (4.3 times and 2.8 times greater at 6 and 12 months post-training, respectively); 72% rate of high course satisfaction; and barriers to improved screening practices, such as time limitations among 60.4% of subjects and 57.6% of their employers, were identified. CONCLUSIONS: This unique training enhances breast-cancer prevention and screening practices and early detection.

Breast Neoplasms↗
PubMed1997

Effectiveness of a teen pregnancy clinic in a managed care setting.

We retrospectively examined the effectiveness of a teen pregnancy clinic at a large multispecialty group between 1991 and 1994 using measurements of statistical differences in intervention and outcome variables. The 72 teens in the intervention group attended significantly more prenatal visits, more postpartum visits and gained more weight than the 33 controls. Other outcome variables such as fetal birth weight, Apgar scores, and neonatal intensive care unit admission showed trends toward improvement, but were not significantly different. We conclude that a teen pregnancy clinic in a managed care setting can be a cost-effective intervention in improving mental and neonatal outcome.

Adolescent↗
PubMed1995

Longitudinal evaluation of a breast cancer training module. Preliminary results.

BACKGROUND: In 1993, the University of Texas M.D. Anderson Cancer Center's Department of Clinical Cancer Prevention began a longitudinal evaluation of its efforts to improve early detection and prevention of breast cancer by training health care professionals in special assessment skills, including how to determine risk and how to teach patients to detect breast cancer early. METHODS: Sixty-three nurses enrolled in the 1-week training module were studied in this descriptive analysis. Their evaluation incorporated not only pretests and post-tests of knowledge and clinical performance but also an employer survey, pretraining and posttraining patient logs, and an assessment of clinical skills in each participant's practice setting. RESULTS: Students made statistically significant gains in measures of general knowledge, clinical knowledge and performance, and routine practice of risk assessment, risk counseling, and history taking and physical examination of old (i.e., familiar) patients. Furthermore, the number of patients screened, patients referred, and cancer diagnoses made increased significantly over time, not only between pretraining and posttraining at 6 and 12 months, but also between 6 and 12 months' posttraining. CONCLUSIONS: After learning and practicing new skills, participants successfully incorporated and maintained them and increased referrals and cancers detected, thereby improving the effectiveness of cancer screening.

Breast Neoplasms↗
PubMed1995

Parentage analysis within a semi-free-ranging group of Barbary macaques Macaca sylvanus.

This study of a group of semi-free-ranging Barbary macaques Macaca sylvanus aimed to determine paternity, to establish whether any individual male achieved prominent mating success and to assess genetic variability. Analyses involved electrophoresis of 15 blood protein systems and multilocus DNA fingerprinting (isotopic and nonisotopic). Genetic variability was low; only two blood protein systems were polymorphic. Although all DNA-fingerprints were individual-specific, they showed a high average band-sharing index value (0.67). Nevertheless, a combination of all methods permitted inference of paternity in 11 out of 15 (73%) cases tested. Several males from different age classes fathered infants.

Animals↗
PubMed1995

Diaspirin crosslinked hemoglobin (DCLHb) does not affect the anesthetic potency of isoflurane in rats.

Hemoglobin solutions are being developed as oxygen carrying fluids for multiple clinical indications. Despite an early report of accentuation of ether anesthesia, the effect of hemoglobin on anesthetic potency has not been assessed. We assessed the effect of alpha-alpha diaspirin crosslinked hemoglobin (DCLHb) on the anesthetic requirement of isoflurane necessary to keep rats unresponsive to noxious stimuli (1.0 MAC [minimum alveolar concentration]). During isoflurane administration, each rat received one of the following fluid regimens: 44Hct/N-normal hematocrit and volume; 44Hct/H-8.0 ml of donor blood given as a hypervolemic bolus; 30Hct/H-5.0 ml of DCLHb given as an exchange transfusion and 8.0 ml as a hypervolemic bolus; or 16Hct/H-15.0 ml of DCLHb given as an exchange transfusion and 8.0 ml as a hypervolemic bolus. MAC was determined using a standard tail clamp technique. The isoflurane requirement to achieve 1.0 MAC was not different between the four groups. These results are consistent with a hypothesis that DCLHb does not change the anesthetic state.

Anesthesia, Inhalation↗
PubMed1994

Nitrendipine and superoxide dismutase in ischemic renal injury.

The effect of the Ca entry blocker nitrendipine, the antioxidant superoxide dismutase (SOD), and a combination of nitrendipine and superoxide dismutase on postischemic renal function was studied in four groups (n = 24) of rats. The rats in group 1 (n = 6) were the ischemic control and received 10 mL of 0.9% NaCl. Group II (n = 6) received SOD 7.0 mg/kg. Group III (n = 6) received nitrendipine 1 mg/kg. Group IV (n = 6) received nitrendipine 1 mg/kg and SOD 7 mg/kg. After administration, both kidneys were rendered ischemic by cross-clamping the renal vessels for 60 min. Comparison of 24-h creatinine clearance (CCr) for 3 days after reversal of ischemia revealed: (a) nitrendipine alone was the most effective in preserving renal function (p < .05); (b) SOD provided some degree of improvement, but only on day 3 (p < .05); (c) a similar result was detected using a combination of nitrendipine and SOD (p < .05); (d) there was no significant difference between SOD and nitrendipine nor between SOD and the combination of nitrendipine/SOD; (e) there was a significant improvement with nitrendipine when compared to the combination of nitrendipine/SOD (p < .05).

Acute Kidney Injury↗
PubMed1994

Facial fractures.

Emergency room physicians frequently see facial fractures that can have serious consequences for patients if mismanaged. This article reviews the signs, symptoms, imaging techniques, and general modes of treatment of common facial fractures. It focuses on fractures of the mandible, zygomaticomaxillary region, orbital floor, and nose.

Diagnosis, Differential↗
PubMed1993

Primate origins: plugging the gaps.

Recent discoveries of fossil primate specimens have produced several surprises and challenged prevailing views of early primate evolution. Plesiadapiformes, long regarded as 'archaic primates', may perhaps be linked to the peculiar colugos instead. Inferred relationships of the earliest known undoubted primates (adapids and omomyids) are in turmoil. Both groups have been proposed as sources for the simian primates. Although the origin of the simian primates is obscure, new fossil evidence could push it further back by at least 10 million years. Such uncertainties reflect the low sampling level of the primate fossil record, which can potentially also lead to underestimation of times of origin within the primate tree.

Animals↗
PubMed1993

Effects of sex steroids on maternal motivation in the common marmoset (Callithrix jacchus): development and application of an operant system with maternal reinforcement.

We developed an operant paradigm for measuring effects of reproductive steroids on maternal motivation in common marmosets (Callithrix jacchus). Conditioned response regulated females' exposure to maternal reinforcement. Nulliparous females (n = 15) with experience with infants in social groups were subjects. The paradigm was validated by examining (a) effects of reinforcing stimuli on affective behavior in a nonoperant paradigm, (b) responsiveness of operant performance to changes in reinforcing stimuli and reinforcement schedule, (c) changes in operant responding due to omission of reinforcement, and (d) relation between operant responding and species-typical maternal behavior. In pregnant females, (n = 4), frequency of bar pressing and estradiol:progesterone ratio were maximal just before birth. Nonpregnant females (n = 3) treated with progesterone and estradiol to mimic late-pregnancy steroid profiles showed increased operant maternal behavior.

Acoustic Stimulation↗
PubMed1993

The role of the bone-gallium scan in sternal osteomyelitis.

Sternal osteomyelitis is an uncommon but serious complication of the median sternotomy incision. Between 1982 and 1990, 160 patients with sternal osteomyelitis and wound dehiscence were treated with sternal debridement and pectoral muscle flap closure at The Toronto Hospital. Most of these wound infections were clinically obvious, and the need for surgical treatment apparent. In a small number of patients, however, the extent of the infection was more difficult to determine clinically. In this subset of patients, the interpretation of the bone-gallium scan was important in determining the presence or absence of bone infection and the probability of successful treatment without surgery. In this study, we review our findings at the time of surgery and compare them with the preoperative information available from the bone-gallium scan. The limited literature on this topic is reviewed. In this group of patients, we found the bone-gallium scan was not helpful in clinical management.

Aged↗