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K Davis

Publications and source records attributed to K Davis.

At least 145 records · Page 8Linked to original sources
PubMed1997

Comparison of neurotensin responses to MDL 100,907, a selective 5HT2A antagonist, with clozapine and haloperidol.

The unique pharmacological profile of atypical antipsychotics, such as clozapine, suggests that action on non-dopaminergic transmitter systems might contribute to the unique therapeutic benefits of these drugs. In order to test this possibility, the response of neurotensin systems to drugs with antipsychotic potential was examined because of this peptide's putative association with psychiatric disorders. The effects of treatments by haloperidol, clozapine, and MDL 100,907 (a selective 5HT2A antagonist thought to have antipsychotic activity) on NT pathways were determined in various extrapyramidal and limbic regions and compared. The response of neurotensin systems was determined by measuring neurotensin-like immunoreactivity after 1, 2, 4, and 5 drug administrations. It was observed that tissue content of this peptide in caudate and nucleus accumbens regions tended to be elevated after 1 or 2 drug administrations, but had either returned or was returning to control levels after 4 or 5 drug administrations. In general, the extrapyramidal and limbic neurotensin levels responded in a similar manner to clozapine and the 5HT2A antagonist, but differently for haloperidol in most regions examined. An important exception was in the nucleus accumbens, where all three drugs had similar effects on neurotensin tissue levels. These results suggest that 5HT2A receptors exert basal control over some extrapyramidal and limbic neurotensin systems and this interaction might contribute to the antipsychotic effects of these drugs.

Animals↗
PubMed1997

Expansion of restricted cellular immune responses to HIV-1 envelope by vaccination: IL-7 and IL-12 differentially augment cellular proliferative responses to HIV-1.

The failure of immune effector mechanisms to control HIV-1 infection has important consequences for the human host. In a randomized cohort of HIV-infected patients, there was striking in vitro restriction of the proliferative response to HIV-1 envelope protein (Env), gp160; only 34% of patients recognized Env. Therapeutic vaccination with recombinant gp160 or gp120 (rgp160, rgp120) reversed the restriction in vitro, with Env recognition rising to 81%. Peripheral blood mononuclear cells (PBMC) from HIV-infected vaccine recipients, placebo recipients, and seronegative volunteers were cultured with exogenous IL-7 or IL-12 and either tetanus toxoid (TT) or gp160. IL-7 significantly augmented proliferative responses to TT and gp160, whereas IL-12 only affected proliferation to gp160. IL-7, but not IL-12, increased the number of HIV-infected placebo recipients who recognized rgp160. IL-12 had its greatest effect in the induction of rgp160-specific responses from seronegative individuals. The data suggest that these two cytokines have differential activity in the relief of restricted cellular immunity to Env; the predominant effect of IL-7 is in individuals who have been primed by exposure to antigen, while the effect of IL-12 is most evident in seronegative, unprimed individuals. Modification of restricted proliferative responses to Env by vaccination or cytokines in vitro suggests that strategies incorporating IL-7 or IL-12 as adjuvants may selectively boost cellular reactivity to HIV-1.

AIDS Vaccines↗
PubMed1997

Organization, development, and effects of infraorbital nerve transection on galanin binding sites in the trigeminal brainstem complex.

Previous experiments from this laboratory have indicated that transection of the infraorbital nerve (ION, the trigeminal [V] branch that supplies the mystacial vibrissae follicles) at birth and in adulthood has markedly different effects on galanin immunoreactivity in the V brainstem complex. Adult nerve transection increases galanin immunoreactivity in the superficial layers of V subnucleus caudalis (SpC) only, while neonatal nerve transection results in increased galanin expression in vibrissae-related primary afferents throughout the V brainstem complex. The present study describes the distribution of binding sites for this peptide in the mature and developing V ganglion and brainstem complex and determines the effects of neonatal and adult ION damage and the associated changes in galanin levels upon their distribution and density. Galanin binding sites are densely distributed in all V brainstem subnuclei and are particularly dense in V subnucleus interpolaris and the superficial layers of SpC. They are present at birth (P-0) and their distribution is similar to that in adult animals. Transection of the ION in adulthood and examination of brainstem 7 days later indicated marked reductions in the density of galanin binding sites in the V brainstem complex. With the exception of the superficial laminae of SpC, the same reduction in density remained apparent in rats that survived > 45 days after nerve cuts. Transection of the ION on P-0 resulted in no change in the density of galanin binding sites in the brainstem after either 7 or > 60 days survival. These results indicate that densely distributed galanin binding sites are present in the V brainstem complex of both neonatal and adult rats, that they are located in regions not innervated by galanin-positive axons, and that their density is not significantly influenced by large lesion-induced changes in the primary afferent content of their natural ligand.

Afferent Pathways↗
PubMed1997

Molecular analysis of the NF2 tumor-suppressor gene in schwannomatosis.

Patients with multiple schwannomas without vestibular schwannomas have been postulated to compose a distinct subclass of neurofibromatosis (NF), termed "schwannomatosis." To compare the molecular-genetic basis of schwannomatosis with NF2, we examined the NF2 locus in 20 unrelated schwannomatosis patients and their affected relatives. Tumors from these patients frequently harbored typical truncating mutations of the NF2 gene and loss of heterozygosity of the surrounding region of chromosome 22. Surprisingly, unlike patients with NF2, no heterozygous NF2-gene changes were seen in normal tissues. Examination of multiple tumors from the same patient revealed that some schwannomatosis patients are somatic mosaics for NF2-gene changes. By contrast, other individuals, particularly those with a positive family history, appear to have an inherited predisposition to formation of tumors that carry somatic alterations of the NF2 gene. Further work is needed to define the pathogenetics of this unusual disease mechanism.

Adolescent↗
PubMed1997

The use of nurse practitioners in the acute care setting.

A collaborative practice model was initiated in a university hospital to assist resident physicians to coordinate patient care on specialty services. Nurse practitioner (NP) data were collected on daily work activities and categorized as direct care, indirect care, administration, education, and research. Satisfaction surveys were collected from patients, physicians and nursing staff. Data on clinic evaluation and management service provided by the NPs were reported. The study supported the appropriateness of NPs in the acute care setting.

Hospitals, University↗
PubMed1997

Combined differential lung ventilation and inhaled nitric oxide therapy in the management of unilateral pulmonary contusion.

Unilateral pulmonary contusion after blunt thoracic trauma can prove to be a devastating injury. Regional disturbances in blood flow and alveolar ventilation can significantly alter pulmonary function. We present a case report of unilateral pulmonary contusion that resulted in significant pulmonary dysfunction. This patient was successfully managed with multimodality therapy consisting of differential lung ventilation and inhaled nitric oxide. The effect of nitric oxide applied to the "normal" lung, the "injured" lung, and both lungs is described. The use of inhaled nitric oxide was associated with an increase in oxygenation when applied to the normal or both lungs. The use of nitric oxide in conjunction with differential lung ventilation appeared to offer benefit in this patient with severe unilateral pulmonary contusion.

Adult↗
PubMed1997

Impact of the in-house trauma surgeon on initial patient care, outcome, and cost.

BACKGROUND: The purpose of this study is to evaluate the effect of having attending trauma surgeons with added qualifications in surgical critical care present for the initial resuscitation at a regional trauma center. METHODS: This study is a retrospective review of patients admitted between August of 1994 and December of 1995 from our trauma registry. The patients were categorized by the call preference of the admitting physician as in-house (IH) or call-back from home (CB), day of admission (weekend vs. weekday), time of admission (AM VS. PM), and a value of the injury severity scale < or = 15 or > 15. Demographics, admission vital signs, Injury Severity Scale, Glasgow Coma Score, and elapsed time to diagnostic, therapeutic, and/or operative interventions were studied. The effect on intensive care unit length of stay, mortality, and hospital cost for resuscitation were also studied. RESULTS: The study population consisted of 1,043 patients. The IH and CB groups each included two attending surgeons. IH significantly reduced the average time to completion of diagnostic peritoneal lavage (22 vs. 34 minutes; p < 0.05), therapeutic intervention (21 vs 38 minutes; p < 0.05), and transport to the operating room (206 vs. 312 minutes; p < 0.05) during the AM compared with CB. There was no difference in these times for the PM admissions. There was no significant difference in intensive care unit length of stay. Among patients with severe head and thoracoabdominal injury (Abbreviated Injury Score > 4 and 3, respectively) there was no difference in mortality. Analysis of cost for emergency room resuscitation in severely injured patients (Injury Severity Score > or = 15), seen during weekdays, was significantly less when evaluated by IH (IH = $5,097 vs. CB = $6,779; p < 0.05). CONCLUSIONS: During the initial resuscitation of patients with severely injured during the weekdays, IH significantly reduced the cost, and elapsed time to diagnostic testing, therapeutic intervention, and to the operating room, respectively. IH reduced fatalities compared with CB.

Adult↗
PubMed1997

Inhaled nitric oxide in acute respiratory distress syndrome.

BACKGROUND: Inhaled nitric oxide has been shown to improve oxygenation in select patients with acute respiratory distress syndrome (ARDS). OBJECTIVE: The purpose of this study was to evaluate the clinical response to four concentrations of inhaled nitric oxide (NO) in 20 patients with ARDS. METHODS: All patients with ARDS were eligible for the study. ARDS was defined as (1) the presence of a predisposing factor; (2) a PaO2/FiO2 ratio < 200; (3) bilateral infiltrates on chest radiograph; and (4) absence of evidence of congestive heart failure and pulmonary artery wedge pressure < 18 mm Hg. Patients received each of four doses (1, 15, 30, and 60 ppm) in random order, each for a 3-hour period. Cardiovascular variables were continuously monitored, and arterial and mixed venous blood gas measurements were obtained at 30 minutes and 3 hours. RESULTS: Thirteen of the 20 patients demonstrated a significant increase in their PaO2/FiO2 (> 20% increase) when treated with inhaled NO. The administration of inhaled NO was associated with an increase in oxygenation at doses of 1, 15, and 30 ppm, but not 60 ppm. Increasing NO dose to more than 1 ppm did not significantly improve response. Mean pulmonary artery pressure decreased with increasing NO concentration, but this did not reach statistical significance. Nine of the 13 responding patients and 2 of the 7 nonresponding patients survived. CONCLUSION: Inhaled NO was successful in increasing PaO2/FiO2 by > 20% in 65% of the surgical patients in this trial. Response to NO could not be predicted by initial PaO2/FiO2 or pulmonary artery pressures. A trial of inhaled NO at a dose of < 10 ppm may be helpful in ARDS patients requiring increasing FiO2 and positive end-expiratory pressure.

Administration, Inhalation↗
PubMed1997

Neonatal airway colonization with gram-negative bacilli: association with severity of bronchopulmonary dysplasia.

BACKGROUND: Airway colonization with Gram-negative bacilli (GNB) and Gram-positive cocci (GPC) is common in mechanically ventilated neonates. Whether GNB are related to nosocomial bloodstream infection (BSI) and/or to the severity of bronchopulmonary dysplasia (BPD) is unknown. METHODS: We prospectively examine this relationship using a cohort design. Data from 260 < or = 1250-g birth weight inborn infants (1991 to 1995) intubated > or = 2 weeks included 917 serial tracheal cultures and 583 blood cultures. The severity of BPD was assessed by duration of mechanical ventilation, oxygen dependency at 36 weeks of postconceptional age and the use of home oxygen supplementation. RESULTS: After 2 weeks of ventilation, 80% of the infants were colonized with GPC (Staphylococus epidermidis and Staphylococcus haemolyticus in 90% of the cases). Superimposed on 36% of these infants was GNB airway colonization with Klebsiella pneumoniae (25%), Enterobacter cloacae (25%), Escherichia coli (25%), Pseudomonas aeruginosa (10%), Serratia marcescen (10%), Acinetobacter baumannii and Haemophilus influenzae (5%). Comparison between 174 GPC- and 86 GNB-colonized infants showed that demographics, birth weight, gestational age, perinatal risk factors and mortality were similar. Fifteen percent of GNB-colonized infants developed BSI caused by GNB and 14% developed BSI caused by GPC. No significant temporal relationship between airway colonization and BSI was noted. GNB infants were ventilated longer and required oxygen at 36 weeks of postconceptional age and home oxygen supplementation twice as often as infants colonized only with GPC. GNB colonization was a predictor of severe BPD after controlling for ventilation. Ureaplasma colonization occurred in 28% of GNB-colonized and 33% of noncolonized infants and was not a predictor of BPD severity. CONCLUSION: GNB airway colonization creates a moderate risk for BSI. Antibiotic treatment does not regularly eradicate GNB. GNB airway colonization is associated with severe BPD, but further studies will be necessary before therapeutic efforts to eradicate GNB from the airways should be undertaken.

Bronchopulmonary Dysplasia↗
PubMed1997

Blunt carotid artery injuries.

BACKGROUND: Blunt carotid artery trauma remains a rare but potentially devastating injury. Early detection and treatment remain the goals of management. Our objective was to identify patients sustaining blunt carotid injuries at a regional trauma center and report on the incidence, demographics, diagnostic workup, management, and outcome. STUDY DESIGN: A retrospective chart review was performed of patients sustaining blunt carotid artery injury between 1990 and 1996. RESULTS: Twenty patients were identified during the 7-year period. All patients suffered blunt trauma, with motor vehicle accidents being the most common mechanism, and the internal carotid the most frequently injured vessel. Associated injuries were present in all patients, with head (65%) or chest (65%) injuries being the most common. The combination of head and chest trauma (45%) was found to be associated with a 14-fold increase in the likelihood of carotid injury. Cerebral angiography was diagnostic in all patients and the majority were treated nonoperatively with anticoagulation. Twenty percent of patients were discharged with a normal neurologic exam, while 45% left with a significant neurologic deficit. Overall mortality was 5%. CONCLUSIONS: Blunt carotid injuries are rare but are associated with significant morbidity and mortality. The combination of craniofacial and chest wounds should raise the index of suspicion for blunt carotid injury. Anticoagulation was associated with the least morbidity.

Adolescent↗
PubMed1997

The economic impact on families of children's participation in junior sport.

The study investigated the socio-economic consequences for families of participation in junior sport. Two hundred and twenty families in Queensland and Victoria were surveyed from the sports of cricket, Australian football, gymnastics, hockey, netball and tennis and twenty seven of these interviewed. The study showed that parents make a substantial contribution in terms of financial support to their children's participation in junior sport. Each of the sports mode different financial demands on families depending on the yearly cycle of training and competition, distance from facilities and coaching, costs associated with coaching, equipment and uniforms, and representative level. It is concluded that family income and structure are the key factors in determining the likelihood of a child's involvement in junior sport, and that for many Australian children, financial factors may be barriers to their participation in junior sport.

Adolescent↗
PubMed1997

Effect of citrate concentration in specimen collection tubes on the International Normalized Ratio.

PROBLEM: Does citrate concentration in specimen collection tubes affect the International Normalized Ratio? METHODS: The International Normalized Ratio was determined on quadruplicate plasma specimens from 32 patients treated long term with oral anticoagulants-two from tubes with 3.2% citrate and two with 3.8% citrate. Two laboratories, using two different coagulometers, tested the specimens. RESULTS: International Normalized Ratios of plasma from tubes with 3.8% citrate were significantly higher than those from tubes with 3.2% citrate when tested with either coagulometer. Patients given adequate anticoagulation on the basis of the International Normalized Ratio at one concentration of citrate appeared either overanticoagulated and at risk of bleeding or underanticoagulated and at risk of thromboembolism at the other concentration of citrate. CONCLUSION: Results emphasize the need for using a single concentration of citrate for prothrombin time testing. We recommend 3.2% citrate.

Anticoagulants↗