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Biomedical subjects

T W Smith

Publications and source records attributed to T W Smith.

At least 55 records · Page 3Linked to original sources
PubMed1998

Support for new policies to regulate firearms. Results of two national surveys.

BACKGROUND: New policy options are emerging in the debate regarding the regulation of firearms in the United States. These options include the treatment of firearms as consumer products, the design of which can be regulated for safety; denial of gun ownership to those convicted of misdemeanors; and strategies to curtail the illegal sale of guns. The public's opinion of these innovative gun-policy options has not been thoroughly assessed. METHODS: We conducted two telephone surveys of 1200 adults each in the United States in 1996 and 1997-1998. Cognitive interviews and pretests were used in the development of the survey instruments. Potential participants were then contacted by random-digit dialing of telephone numbers. RESULTS: A majority of the respondents favored safety standards for new handguns. These standards included childproofing (favored by 88 percent of respondents), personalization (devices that permit firing only by an authorized person; 71 percent), magazine safeties (devices that prevent firing after the magazine or clip is removed; 82 percent), and loaded-chamber indicators (devices that show whether the handgun is loaded; 73 percent). There was strong support for policies prohibiting persons convicted of specific misdemeanors from purchasing a firearm. Support for such prohibitions was strongest for crimes involving violence or the illegal use of a firearm (83 to 95 percent) or substance abuse (71 to 92 percent). There was also widespread support for policies designed to reduce the illegal sale of guns, such as mandatory tamper-resistant serial numbers (90 percent), a limit of one handgun purchase per customer per month (81 percent), and mandatory registration of handguns (82 percent). Even among the subgroup of respondents who were gun owners, a majority were in favor of stricter gun regulations with regard to 20 of the 22 proposals covered in the poll. CONCLUSIONS: Strong public support, even among gun owners, for innovative strategies to regulate firearms suggests that these proposals warrant serious consideration by policy makers.

Adult↗
PubMed1998

Internists' and surgeons' attitudes toward guns and firearm injury prevention.

BACKGROUND: The high rates of death, injury, and long-term disability related to firearms in the United States have led to growing concern in the health care community. Medical organizations and journals are devoting increasing attention to firearm violence as a public health problem; however, few reports discuss physician attitudes toward guns and prevention of firearm-related injury. OBJECTIVE: To determine internists' and surgeons' attitudes toward guns and firearm injury prevention. DESIGN: Analysis of results of a structured telephone interview. SETTING: Internal medicine and surgical offices. PARTICIPANTS: 457 internists and 458 surgeons. MEASURES: 55 questions that covered six domains: experience with firearms, knowledge about clinical sequelae of firearm injury, knowledge about public policies on firearm violence, attitudes toward public policies on firearm violence, clinical practice behavior, and education and training. RESULTS: The interview response rate was 45.3%, with a compliance rate of 82.5% and a 95% probability (error rate, +/- 5%). Ninety-four percent of internists and 87% of surgeons believe firearm violence is a major public health issue. A majority of internists and surgeons also support community efforts to enact legislation to restrict the possession or sale of handguns (84% and 64%, respectively). Furthermore, although 84% of internists and 72% of surgeons believe that physicians should be involved with firearm injury prevention, less than 20% of respondents usually engage in some form of firearm injury prevention practice in patient care. CONCLUSION: Many internists and surgeons think that firearm injuries are a public health issue of growing importance, that physicians should incorporate firearm safety screening and counseling into their practice, that physicians should join community efforts to regulate handguns, and that specific gun regulation measures should be adopted as public policy.

Adult↗
PubMed1998

The medial temporal lobe in dementia with Lewy bodies: a comparative study with Alzheimer's disease.

The usefulness of determining medial temporal lobe (MTL) size in differentiating Alzheimer's disease (AD) from other dementia subtypes is unknown. We compared the cross-sectional areas of the MTLs in histological sections from the brains of 18 patients with dementia with Lewy bodies (DLB) but lacking AD changes, 24 DLB patients with concurrent AD pathology, 20 pure AD cases, and 18 age-matched control cases. Duration and severity of disease were comparable between groups. When data for cross-sectional area were expressed as percentages of the average control area, DLB MTLs were significantly larger than either AD or DLB/AD MTLs at rostral levels (86 +/- 16%, 54 +/- 17%, and 66 +/- 23% of control areas, respectively). At caudal levels, DLB MTLs were larger than AD MTLs (80 +/- 20%, 59 +/- 21%, and 77 +/- 26% of control areas in DLB, AD, and DLB/AD, respectively). MTL cross-sectional area often approaches normal in pure DLB, even when disease duration is prolonged and symptoms are end stage. In contrast, a greatly reduced MTL area mitigates against the diagnosis of DLB, unless there are concurrent AD changes.

Aged↗
PubMed1998

Regulation of cardiac myocyte contractile function by inducible nitric oxide synthase (iNOS): mechanisms of contractile depression by nitric oxide.

Inflammatory cytokines have been implicated in the reversible depression of cardiac contractile function accompanying local or systemic immune stimulation. Incubation of cardiac myocytes with soluble components in the supernatant from cultured rat lung macrophages activated with endotoxin decreases their contractile response to beta-adrenergic stimulation through the induction of iNOS and the subsequent production of nitric oxide by these cells. In the present study, we characterize the mechanisms underlying NO's attenuation of adrenergic responsiveness in cardiac myocytes. iNOS was induced in cultured ventricular myocytes from adult rats by incubation for 20 h with conditioned medium from lipopolysaccharide (LPS)-activated macrophages. iNOS induction did not induce any alteration in beta-adrenergic receptor density or affinity, Galphai protein abundance, or adenylyl cyclase activity in cultured myocytes. Myocyte exposure to activated macrophage-conditioned medium markedly attenuated the elevation of cAMP in response to isoproterenol (Iso, 2 nM). Induction of iNOS with the macrophage-conditioned medium also potentiated the Iso-induced increase in myocyte cGMP. This cGMP increase was totally abolished by NOS inhibitors. NOS inhibition also returned the attenuated cAMP response to 2 nM Iso to levels observed in control cells. Pre-incubation of the cells in isobutylmethylxanthine (IBMX), a phosphodiesterase inhibitor, also partly reversed the attenuation of cAMP increase with 2 nM Iso in cells expressing iNOS. Brief (15 min) exposure of myocytes to the NO donor, S-nitrosoacetylcysteine (SNAC, 100 micro M) which produced a three-fold increase in intracellular cGMP, also decreased by half the contractile response of cardiac myocytes to Iso (2 nM). We conclude that NO endogenously produced by iNOS decreases the intracellular levels of cAMP in response to beta-adrenergic stimulation in isolated cardiac myocytes, in part through a cGMP-mediated mechanism. This effect may participate in the NO-dependent depression of cardiac function following cytokine exposure.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Perceptions of spouse dominance predict blood pressure reactivity during marital interactions.

Cardiovascular reactivity (CVR) has been identified as a potential mechanism linking a variety of psychosocial processes to the development of cardiovascular disease. Although the effects of hostile and supportive social stimuli on CVR have been studied extensively, less is known about the effects of a second major dimension of social relations--dominance versus submissiveness. In the present study, 45 married couples participated in an interaction task involving the assertion of differing opinions. Subjects also provided ratings of their typical level of dominance versus submissiveness in relation to their spouse. Consistent with predictions derived from related conceptual models of psychological determinants of CVR, blood pressure reactivity was positively associated with perceptions of the spouse as dominant. At the highest level of perceived spouse dominance, CVR was attenuated, again consistent with prediction. Results are discussed in terms of the usefulness of conceptual models of interpersonal relations and motivation as guides in studying the social determinants of CVR, as well as the value of marital interactions as a context for understanding CVR.

Adult↗
PubMed1998

Ki-67 (clone MIB-1) proliferation index in recurrent glial neoplasms: no prognostic significance.

BACKGROUND: To determine if the Ki-67 (MIB-1 clone) proliferative index (PI) has prognostic potential in patients with recurrent astroglial neoplasms. METHODS: We conducted a retrospective review of 27 patients whose initial and recurrent specimens were available. Histopathology was determined according to the World Health Organization classification. Proliferation index was calculated on formalin-fixed tissue using the Ki-67 (MIB-1 clone) antibody. Morphometric data were analyzed in conjunction with clinical data and Cox Proportionate Hazards Analysis, Spearman's correlation coefficient and Mann-Whitney Test. RESULTS: Initial histopathology included 14 glioblastoma multiforme, 7 anaplastic astrocytoma, 3 oligoastrocytoma, and 3 astrocytoma. Recurrent specimens showed changes consistent with treatment. While univariate analysis shows initial histology correlated with survival (p<0.036), PI did not correlate with survival after either initial (p = 0.86) or recurrent (p = 0.46) surgery for any tumor type. PI difference between specimens also did not correlate with survival (p = 0.91). Initial PI did not correlate with recurrent PI either (p = 0.43). CONCLUSIONS: Ki-67 PI does not confer additional prognostic information for patients with recurrent astroglial neoplasms. One possible explanation for this observation is that treatment may alter the PI independent of its effect on tumor growth.

Adult↗
PubMed1998

Bone loss around 2 different types of hip prostheses.

Dual energy x-ray absorptiometry (DXA) allows the measurement of bone mineral density (BMD) around an uncemented hip prosthesis. The aims of this study were: 1) to determine the reproducibility of periprosthetic BMD measurements; 2) to delineate the time course of bone loss that occurs after insertion of a hip prosthesis; and 3) to compare the bone loss around two different types of hip prosthesis. We studied 20 patients: 11 had Bateman and 9 had porous-coated anatomic prostheses inserted. The mean bone loss in 20 patients between 6 and 52 weeks after surgery was 6%. The greatest loss during this period was 18% and occurred from the proximal medial cortex. We conclude that measurement of periprosthetic bone mass by DXA is a precise technique. Bone loss was rapid in the first 6 months following total hip replacement. There was no difference in the bone loss occurring around the two prostheses studied.

Absorptiometry, Photon↗
PubMed1998

Intracranial leiomyosarcoma: a neuro-oncological consequence of acquired immunodeficiency syndrome.

Leiomyosarcoma has recently been identified as an AIDS-related tumor, usually occurring in children in the chest or abdomen. We describe a case of intracranial leiomyosarcoma in an adult with AIDS. An enhancing mass adjacent to the right occipital cortical surface was diagnosed during a work-up for left arm weakness. Imaging characteristics were suggestive of a malignant neoplasm versus meningioma. The patient had a craniotomy for total excision of the lesion. Pathology showed a leiomyosarcoma. Metastatic work-up was negative. The patient refused radiation therapy, but is well without evidence of recurrence at 8 months follow-up. The differential diagnosis for intracranial lesions in AIDS should be expanded to include leiomyosarcoma. Surgical resection of the lesion is recommended.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Sibling interactions, self-regulation, and cynical hostility in adult male twins.

Chronic hostility is associated with increased vulnerability to serious physical illness, making developmental influences on this trait important. We used the Structural Analysis of Social Behavior (SASB) model to examine retrospective descriptions of twin interactions during childhood in a sample of 48 adult male twin pairs. Consistent with previous research on parental behavior correlates, self-reported hostility as measured by the Cook and Medley Ho scale was associated with descriptions of the twin's behavior as hostile, controlling, and neglecting. Consistent with the SASB principle of introjection, hostility was also associated with self directed hostility and neglect. Thus, a developmental perspective not only describes possible social contexts involved in the emergence of this trait, but also suggests possible psychological underpinnings. Implications for models of hostility and health are discussed.

Adult↗
PubMed1998

Agency, communion, and cardiovascular reactivity during marital interaction.

The concepts of agency and communion have been used to describe sex differences in vulnerability to specific stressor domains. This study examined blood pressure and heart rate responses of 60 married couples to experimental manipulations of disagreement (i.e., communion stressor) and achievement challenge (i.e., agency stressor). Consistent with predictions, disagreement elicited heightened cardiovascular reactivity among wives, but not husbands. In contrast, the achievement challenge elicited heightened cardiovascular reactivity among husbands, but not wives. Participants' responses to a circumplex measure of interpersonal appraisal were consistent with the interpretation of differential responses to agency and communion stressors. Results are congruent with a situational approach to sex differences in cardiovascular reactivity and illustrate the utility of interpersonal methods in the explication of psychosocial risk for cardiovascular disease.

Adult↗
PubMed1998

Geographic distribution of ticks (Acari: Ixodidae) in Michigan, with emphasis on Ixodes scapularis and Borrelia burgdorferi.

A 12-yr (1985-1996) passive survey in Michigan based upon tick submissions from citizens yielded 4,755 ticks of 21 species, 16 of which were probably indigenous in the state. Three species of Dermacentor [most common, D. variabilis Say and D. albipictus (Packard)]; 2 species of Amblyomma [most common, A. americanum (L.)]; and 12 species of Ixodes (most common, I. cookei Packard and I. scapularis Say), as well as Haemaphysalis leporispalustris (Packard), Rhipicephalus sanguineus Latreille, and the soft ticks Ornithodoros kelleyi Cooley & Kohls, and Otobius megnini (Duges) were submitted. New state records were I. kingi Bishopp, I. texanus Banks, I. sculptus Neumann, and I. baergi Cooley & Kohls. Examination of gut smears from dissections of 1,037 ticks of 13 species by indirect immunofluorescent assay, using murine monoclonal H9724 as the primary antibody, revealed that 11 of 175 I. scapularis were infected with Borrelia spp. All positive I. scapularis were from Menominee County in the upper peninsula of the state, which also provided 79.8% of all submitted I. scapularis. Surveys for ticks on 5,449 hunter-killed white-tailed deer were conducted from 1988 to 1990, encompassed deer taken from 65 of the state's 83 counties, and showed that although D. albipictus was distributed widely in the northern part of the state, I. scapularis occurred only on deer taken from southern townships of Menominee County. Of 1,218 canine sera tested for antibodies to B. burgdorferi in 1992 and 1993, 25 of 299 (8.0%) from Menominee County were positive but only 1 of 919 sera submitted from 5 counties in the lower peninsula was positive.

Animals↗
PubMed1998

Broiler breeder age and dietary fat influence the yolk fatty acid profiles of fresh eggs and newly hatched chicks.

The purpose of the present study was to investigate the combined effects of breeder age (36-, 51-, or 64-wk) and different dietary fat sources (3% added corn oil, poultry fat, or lard) on lipids in fresh egg yolks and yolks of newly hatched chicks. Isocaloric breeder diets were altered by the inclusion of different types of dietary fat such that the poultry fat and lard diets had the highest levels of saturated fatty acids when compared to the corn oil diet. Fresh egg yolks obtained from 36-wk-old breeders exhibited higher levels of palmitoleic acid when compared to the levels observed in fresh egg yolks of 51- or 64-wk-old breeders. Furthermore, these levels decreased significantly by 21 d of incubation only in eggs from 36-wk-old hens. At 36 wk of breeder age, the levels of oleic and arachidonic acid were higher in yolks from hatched chicks than in previous fresh egg values, regardless of type of added dietary fat; whereas the level of linoleic acid was higher only in yolks from hatched chicks compared to those of fresh eggs from 36-wk-old hens fed 3% added corn oil. These data suggest that breeder age influences the utilization of yolk lipid by developing embryos, and that the type of fat provided in the diet may have an additional influence.

Adipose Tissue↗
PubMed1998

Effects of dietary fat and eggshell cuticle removal on egg water loss and embryo growth in broiler hatching eggs.

The effects of dietary fat and eggshell cuticle removal on egg water loss, embryo growth, and hatchability were determined in eggs from broiler breeder hens at different ages. Hens were fed isocaloric diets containing one of three different types and levels of added fat. In addition, eggs were either left intact or washed to remove the eggshell cuticle prior to set. Cuticle removal increased egg water loss between 43 and 62 wk. Cuticle removal increased relative wet embryo weight at Week 52 and relative dry embryo weight at 52 and 62 wk. Furthermore, at 62 wk, diet and day of incubation interacted to affect wet embryo weight, and diet variably affected dry embryo weight. No treatment differences were observed for cumulative hatchability, rate of hatch, and relative yolk sac weight at Day 19 of incubation. It was concluded that cuticle removal and the addition of fat to breeder diets may influence embryonic growth without having any subsequent effects on hatchability.

Animal Feed↗
PubMed1998

Use of a sperm analyzer for evaluating broiler breeder males. 1. Effects of altering sperm quality and quantity on the sperm motility index.

A new instrument for assessing mammalian semen attributes, the Sperm Quality Analyzer, was evaluated as a potential tool for determining rooster sperm quality. The Sperm Quality Analyzer measures the "activity" of sperm in a semen sample as the sperm motility index (SMI). The SMI is defined as the number and amplitude of deflections in a light path per second as a result of sperm movement within a capillary tube. In the present study, effects of sperm concentration, viability, and motility on the SMI were evaluated. Peterson broiler breeder males (n = 40) were used as semen donors. In the initial experiment, semen was diluted from 2- to 25-fold and SMI readings were obtained. The SMI was very low in neat semen samples but increased when semen was diluted up to threefold. However, at dilutions greater than fivefold, the SMI decreased. Apparently, sperm concentration in undiluted semen is so great that sperm are unable to move freely within the capillary tube. Maximum SMI values were obtained at sperm concentrations of approximately 1 billion sperm per milliliter. When thawed, dead sperm were mixed with incubated, live sperm, the SMI decreased with decreasing sperm viability even though sperm concentration was constant. Obviously, fewer sperm move across the light beam as sperm mortality increases. When motile, aerobically incubated sperm were mixed at different rates with immotile, anaerobically incubated sperm samples, the SMI increased with increasing concentrations of motile sperm, whereas total sperm concentration was static. In addition, the SMI was strongly correlated with motility scores obtained by microscopic analysis. The Sperm Quality Analyzer provides an estimate of the overall quality of sperm from broiler breeder males by reflecting sperm concentration, viability, and motility in a single value, the SMI.

Animals↗
PubMed1998

Sudden unexpected death from primary posterior fossa tumors.

We report 2 cases of sudden death in which hospital autopsies revealed unsuspected primary posterior fossa neoplasms. The first case was a 3-year-old girl who was found apneic and pulseless in bed and was brought to the hospital moribund and could not be resuscitated. Autopsy revealed a 3-cm ganglioglioma that infiltrated nearly the entire medulla. The second case involved a 39-year-old man who was found asystolic and unresponsive in bed. He was resuscitated and maintained on a ventilator for a few hours, after which life support was withdrawn. Autopsy showed a 5-cm pilocytic astrocytoma arising from the ventral cerebellum and extending into the fourth ventricle and compressing the brain stem. Previously reported cases of clinically unsuspected primary posterior fossa tumors presenting with sudden death are reviewed. Hypotheses for the mechanism of sudden death are presented.

Adult↗
PubMed1998

Improved axon diameter and myelin sheath thickness in facial nerve cable grafts wrapped in temporoparietal fascial flaps.

Injury to the facial nerve in the temporal bone presents a challenge to the recovery of nerve function, in that the fallopian canal in which it lies is poorly vascularized. This study was designed to determine if wrapping an intratemporal facial nerve defect repaired with a cable graft with a well-vascularized temporoparietal fascial (TPF) flap would improve facial nerve regeneration. To evaluate this question, a defect was created in the intratemporal left facial nerve of 10 rabbits. All nerves were repaired using cable grafts. In 5 animals, the nerve graft was wrapped with temporoparietal fascia, whereas in the other 5 rabbits it was not. Three additional animals underwent exposure only. The contralateral nerve served as a control in all animals. Quantitative analysis of the nerve graft 12 weeks after repair revealed greater recovery of original fiber diameter and myelin sheath thickness in TPF flap-wrapped repairs. Histological evidence of improved neural regeneration and functional nerve recovery was also seen in the repairs where the TPF flap was utilized. Nerve conduction and electromyographic studies of the cable-grafted nerve at 6 and 12 weeks were equivocal, however.

Animals↗
PubMed1998

Scar quality from partial or complete wound closure using the Cincinnati incision for clubfoot surgery.

The method of skin closure in using the Cincinnati incision for clubfoot surgery may influence the quality of the scar obtained and the postoperative outcome. We retrospectively reviewed two groups of patients who underwent either primary skin closure (14 feet in 11 patients) or partial wound closure and healing by secondary intention (15 feet in 11 patients). The quality of the scars from both of these methods were equally acceptable cosmetically, and neither technique predisposed the patient to any long-term wound complications. In addition, we noted that closing the skin may act as a soft tissue tether, and that the initial position of the postoperative splinting of the foot may influence the surgical outcome. Both of these factors may contribute to the recurrence of equinovarus deformity.

Cicatrix↗