Biomedical subjects

D D McIntire

Publications and source records attributed to D D McIntire.

58 records · Page 4Linked to original sources

PubMed1991

Hypothyroidism selectively reduces the rate and amount of transport for specific SCb proteins in the hyt/hyt mouse optic nerve.

Thyroid hormone significantly affects molecular and neuroanatomical properties of the developing nervous system. Altered connectivity in hypothyroidism may reflect reductions in process growth, alterations in process maintenance, or changes in synaptogenesis or synaptic maintenance. These events are dependent on microtubules, neurofilaments, microfilaments, and associated molecular components. Reductions in delivery of microtubules and neurofilaments to the distal axon by slow component a (SCa) of axonal transport may contribute to the neuroanatomical abnormalities of hypothyroidism (Stein et al., J Neurosci Res 28:121-133, 1991). However, hypothyroidism might also affect the axon and synaptic connections by altering slow component b (SCb), which includes actin microfilaments and proteins that contribute to synaptic function, i.e., clathrin, HSC70 (clathrin uncoating ATPase), spectrin, and calmodulin. To determine the effect of hypothyroidism on SCb proteins, slow axonal transport was analyzed in optic nerves of hyt/hyt hypothyroid mice, which have severe primary hypothyroidism, and euthyroid control mice. Clathrin, spectrin, HSC70, and actin showed significant reductions in transport velocity in hyt/hyt optic nerves relative to euthyroid nerves, but the transport rate for calmodulin was less affected. However, the amount of calmodulin was significantly elevated in hyt/hyt nerve over euthyroid nerves. Hypothyroidism selectively reduces transport of SCb proteins, which are thought to play significant roles in synaptic function and in the growth cone. The effects of hypothyroidism on microtubules and neurofilaments combined with actions on SCb suggest that changes in neuronal function associated with reduced thyroid hormone during development and maturity (i.e., alterations in neuronal connectivity, nerve conduction, and synaptic function) may be mediated in part by effects on slow axonal transport.

Actins↗

PubMed1991

Pathologic fetal acidemia.

There is no clearly established umbilical artery pH cutoff to be used for defining pathologic fetal acidemia (ie, the threshold associated with major neonatal morbidity or mortality). Classically, a pH cutoff of less than 7.20 has been used. Our goal was to define this pH cutoff more precisely. There were 3506 term newborns (2500 g or greater) with an umbilical artery pH of less than 7.20; these newborns were divided into five pH groups. Eighty-seven (2.5%) had a pH of less than 7.00, 95 (2.7%) a pH of 7.00-7.04, 290 (8.3%) 7.05-7.09, 798 (22.8%) 7.10-7.14, and 2236 (63.8%) 7.15-7.19. Two-thirds (66.7%) of the newborns with an umbilical artery pH less than 7.00 had a metabolic component in their acidemia, compared with 13.7% or less in all other pH groups. Significantly more (P less than .05) newborns in the less-than-7.00 pH group had low (less than 3) 1- and 5-minute Apgar scores compared with the other four pH groups. In addition, neonatal death was significantly more common (P = .03) in newborns with a pH less than 7.00, and seven (50%) of the 14 deaths occurred in this group. The statistically significant pH cutoff for all seizures was less than 7.05 (P = .004), and for unexplained seizures was less than 7.00 (P = .01). Eight (67%) of the 12 unexplained seizures occurred in this latter pH group. Thus, a more realistic pH cutoff for defining pathologic fetal acidemia would appear to be less than 7.00.

Acidosis↗

PubMedDate not supplied

HIV and interventional radiology: a national survey of physician attitudes and behaviors.

PURPOSE: The frequency of parenteral and cutaneous exposure to blood or body fluid during interventional radiologic procedures, current use of barrier precautions by interventional radiologists, and physician attitudes about testing for the human immunodeficiency virus (HIV) and related issues were assessed. MATERIALS AND METHODS: An anonymous survey of interventional radiologists was conducted by mail in November 1991. RESULTS: Of 1,530 surveys, 819 (54%) were returned and 806 (53%) were completed and evaluable. Ninety-six percent of respondents (763 of 794) perform procedures in patients infected with HIV. Sixty-nine percent oppose mandatory testing of physicians for HIV. Eighty-seven percent (693 of 797) reported at least one procedure-related injury (range, 0-99; mean, four). Fifty-eight percent of injuries occurred with use of a sharp instrument (381 of 662), 20% were due to needle recapping (133 of 662), and 7% (44 of 662), to improper disposal of a sharp instrument. Contact between a physician's blood and a patient was reported in only one case (0.2%). Eighty-five percent of respondents (671 of 789) changed their use of barrier precautions in the last 10 years; concerns about HIV were cited by 96% as a reason for change. Reported use of barrier measures was highly variable. CONCLUSION: Exposure to patients' blood or body fluid is not infrequent during interventional radiologic procedures. Exposure of patients to the blood or body fluid of health care workers is rare. Use of recommended precautions in interventional radiology is variable, and practices that could lead to preventable injury remain common. Strategies should be developed to reduce risks even further and to encourage universal compliance with government guidelines.

AIDS Serodiagnosis↗

PubMedDate not supplied

Comparing the smoking behavior of veterans and nonveterans.

OBJECTIVES: The authors analyzed self-reported questionnaire data from the 1987 National Medical Expenditure Survey (NMES) to determine the smoking patterns of veterans. METHODS: Using NMES data, the authors compared veterans versus nonveterans overall, women veterans versus women nonveterans, Vietnam-era veterans versus other veterans, and veterans whose usual source of medical care was the Department of Veterans Affairs (VA) system versus veterans who received care elsewhere. RESULTS: The likelihood of ever having smoked cigarettes was higher for veterans than for nonveterans and for women veterans than for women nonveterans. The prevalence of current smoking was higher for veterans than for nonveterans and higher for those seeking care within the VA system than for other veterans. CONCLUSIONS: Given the enormous health care costs associated with smoking, health promotion efforts should be developed to reduce the high rate of smoking among veterans--especially those who are consumers of VA health care.

Adolescent↗