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Biomedical subjects

T Hill

Publications and source records attributed to T Hill.

At least 37 records · Page 2Linked to original sources
PubMed1999

Efficacy of computerized decision support for mechanical ventilation: results of a prospective multi-center randomized trial.

200 adult respiratory distress syndrome patients were included in a prospective multicenter randomized trial to determine the efficacy of computerized decision support. The study was done in 10 medical centers across the United States. There was no significant difference in survival between the two treatment groups (mean 2 = 0.49 p = 0.49) or in ICU length of stay between the two treatment groups when controlling for survival (F(1df) = 0.88, p = 0.37.) There was a significant reduction in morbidity as measured by multi-organ dysfunction score in the protocol group (F(1df) = 4.1, p = 0.04) as well as significantly lower incidence and severity of overdistension lung injury (F(1df) = 45.2, p < 0.001). We rejected the null hypothesis. Efficacy was best for the protocol group. Protocols were used for 32,055 hours (15 staff person years, 3.7 patient years or 1335 patient days). Protocols were active 96% of the time. 38,546 instructions were generated. 94% were followed. This study indicates that care using a computerized decision support system for ventilator management can be effectively transferred to many different clinical settings and significantly improve patient morbidity.

Adult↗
PubMed1998

Combined liver-kidney transplantation in patients with cirrhosis and renal failure: effect of a positive cross-match and benefits of combined transplantation.

Patients with renal failure after liver transplantation have a particularly poor prognosis. Therefore, in the setting of end-stage renal disease requiring dialysis or severe renal insufficiency that will not improve after liver replacement, combined liver-kidney transplantation (LKT) is the preferred approach. We have adopted a policy of LKT in patients with end-stage liver disease and renal insufficiency undergoing dialysis or with a creatinine clearance less than 35 mL/min and evidence of chronic renal dysfunction. Since 1991, we have performed 208 orthotopic liver transplantations. Fourteen patients (8%) have undergone combined LKT, including 6 patients undergoing hemodialysis. Cytotoxic cross-matches (modified Amos technique and antihuman globulin method) were performed on 13 of 14 patients and were positive in 3 patients. Two patients died less than 4 months after LKT and 12 patients are alive and well. Graft survival censored for patient death was 100% for liver allografts and 93% for renal allografts, with a mean follow-up of 39 +/- 24 months. The most recent serum creatinine level in the patients with the 11 functioning grafts was 1.1 +/- 0.6 mg/dL. Biopsy-proven acute rejection occurred in 50% of simultaneous liver allografts. By contrast, only a single episode (6%) of renal allograft dysfunction was attributable to acute rejection. All rejection episodes occurred in the first 90 days after transplantation and were steroid sensitive. Three of 14 combined procedures were performed in the setting of a positive cytotoxic cross-match. In 2 recent patients, the results were confirmed by positive cross-matches to the donor's T and B cells by flow cytometry. Flow cytometric cross-matches reverted to negative 1 hour after liver transplantation and several hours before the administration of antithymocyte globulin. The cross-matches remained negative on postoperative days 1 and 7. Presently, all 3 patients with a positive cross-match enjoy normal hepatic and renal function at 631, 706, and 2275 days follow-up. Renal scans were performed in 4 LKT recipients not previously undergoing hemodialysis and indicated varying and unpredictable degrees of function in the native and transplanted kidneys. In conclusion, combined LKT can be performed safely and is associated with a low rate of acute rejection, even in the setting of a positive cross-match. Predicting which patients with renal insufficiency will benefit from LKT remains challenging; however, these results suggest that LKT should be encouraged in patients with evidence of irreversible renal insufficiency who require liver transplantation.

Adult↗
PubMed1998

Herpes simplex virus hepatitis in macrophage-depleted mice: the role of massive, apoptotic cell death in pathogenesis.

Infection with herpes simplex virus or hepatitis viruses can lead to fulminant hepatitis, but there is controversy about the underlying conditions needed for such disease. To investigate how the impairment of host defences might be involved, macrophages were depleted by administration of silica to mice before intravenous injection with herpes simplex virus type 1 (HSV-1). Such mice died rapidly and their livers were yellowish and shrunken (acute yellow atrophy), and occasionally grossly haemorrhagic. Small foci of apoptotic cells developed in the liver lobules; these rapidly became confluent and zonal over time. The overall lesion pattern was similar to massive hepatic necrosis, and there was extensive HSV replication in the liver lesions. In the liver, DNA fragmentation characteristic of apoptosis followed the time course of HSV-1 propagation. These findings suggest that one of the underlying conditions for fulminant viral hepatitis may be inadequate macrophage response, and that the massive hepatic damage, often defined as cell necrosis, may actually be apoptosis of liver cells subsequent to virus infection.

Alanine Transaminase↗
PubMed1997

Changes in regional cerebral blood flow following light treatment for seasonal affective disorder: responders versus nonresponders.

BACKGROUND: Several brain imaging studies of antidepressant pharmacologic treatment utilizing single photon emission computed tomography (SPECT) have reported a normalization of deficits in cerebral blood flow (CBF) associated with recovery; other studies report no change, or a reduction in CBF following successful treatment. There have been no published SPECT studies of seasonal affective disorder (SAD) assessing response to light treatment in relation to changes in regional CBF (rCBF). In this study, we sought to test the hypothesis that increases in rCBF would be observed in SAD patients who responded to light treatment. METHODS: Ten depressed patients with SAD underwent functional brain imaging studies with 99mTc-hexamethylpropyleneamine oxime SPECT before and after light treatment. RESULTS: Relative increases in rCBF were observed in all brain regions compared to cerebellum in treatment responders, whereas nonresponders showed no change or decreases in rCBF relative to cerebellum. Significant differences in mean percentage change in rCBF between responders (n = 5) and nonresponders (n = 5) were detected in frontal and cingulate cortex, and thalamus. CONCLUSIONS: These findings provide preliminary support for the hypothesis that an increase in rCBF is associated with recovery from depression in SAD.

Adult↗
PubMed1997

Hidden covariation detection: a fundamental and ubiquitous phenomenon.

H. Hendrickx, J. De Houwer, F. Baeyens, P. Eelen, and E. Van Avermaet (1997) reported a series of (mostly unsuccessful) studies on nonconscious hidden covariation detection (HCD); for example, they reported that out of 3 attempts to replicate P. Lewicki et al.'s studies, only 1 produced the expected results. They concluded that HCD may be not as general and robust as the previous research suggested, and they considered boundary conditions. In this article, the authors discuss a number of weaknesses of H. Hendrickx et al.'s experiments (and systematic deviations from the original methodology) that are potentially responsible for the lack of the expected results and discuss missing facts in their arguments (e.g., they failed to mention any published replications of the HCD studies from other than the present authors' laboratories). It is argued that when all evidence is considered, the proper conclusion is that nonconscious processing of covariations is not only general and robust but also a ubiquitous phenomenon mediating a variety of processes of acquisition of information.

Humans↗
PubMed1997

Gestational herpes simplex virus hepatitis.

Hepatitis due to herpes simplex virus (HSV) is unusual in healthy individuals. To date, only 56 cases of HSV hepatitis in adult patients have been reported, including 21 pregnant patients. We describe a 25-year-old white woman in her 30th week of gestation who had progressive acute hepatitis. Histologic examination of the liver biopsy specimen showed diffuse microabscesses involving more than 50% of the hepatic parenchyma, with multiple hepatocytes containing Cowdry type A and ground-glass nuclear inclusions. The diagnosis of herpes hepatitis was confirmed by positive immunoreactivity to HSV antibodies in the tissue sections. Intravenous acyclovir therapy was immediately initiated, and the patient's condition improved dramatically. She then had a normal baby at term. Subsequently, the patient had a second pregnancy and an uncomplicated vaginal delivery without recurrence of the disease. Even though alterations of the humoral and cell-mediated immunity occur during pregnancy, herpes hepatitis is rare in pregnant women. Since the prompt administration of antiviral drugs is a lifesaving measure, we recommend including HSV hepatitis in the differential diagnosis of acute hepatitis in pregnancy.

Acute Disease↗
PubMed1997

Localization of Neuroendocrine Tumors Using Somatostatin Receptor Imaging With Indium-111-Pentetreotide (OctreoScan).

BACKGROUND: Many imaging methods have been used to detect neuroendocrine tumors of the gastrointestinal system. There is no gold standard for identifying the location of primary tumors and their potential metastases, and most conventional imaging techniques cannot detect tumors less than 1.0 cm in size. METHODS: The authors have investigated the use of 111-In-pentetreotide as an imaging agent for abdominal neuroendocrine tumors. RESULTS: The agent is cleared rapidly by the kidneys and is primarily excreted intact with a biologic half-life of six hours. The largest radiation burden is to the spleen and kidneys. A nine-center study conducted in Europe involved 365 patients with gastroenteropancreatic neuroendocrine tumors that were also imaged by other methods. The results of 111-In-pentetreotide were in agreement with those obtained by other methods for 79% of tumor locations. An additional 110 tumor localizations were detected that were not seen with conventional methods. The smallest gastrinoma imaged by 111-In-pentetreotide was a 4-mm duodenal tumor. CONCLUSIONS: Scintigraphy with 111-In-pentetreotide is effective in visualizing various somatostatin receptors characteristic of neuroendocrine tumors of the gastrointestinal tract. Insulinomas, however, are not well imaged. Concurrent computed tomography scanning is advised to minimize the risk of missing liver metastases.

Journal Article↗
PubMed1996

Regional cerebral blood flow changes after light therapy in seasonal affective disorder.

There is considerable evidence to indicate that depressive disorders may be associated with changes in regional cerebral blood flow (rCBF), and that successful treatment may reverse these changes. We studied patients with seasonal affective disorder (SAD) using 99Tcm-hexamethylpropylene amine oxime (99TCm-HMPAO) single photon emission tomography (SPET) to examine the effect of light therapy on rCBF. Ten depressed patients (8 females, 2 males) with a mean (+/- S.D.) age of 33.5 +/- 11.3 years underwent 99TCm-HMPAO SPET studies before and after light therapy. The treatment response was evaluated using the Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorders Version (SIGH-SAD). A patient was considered responsive to light therapy if the post-treatment SIGH-SAD score was reduced by 60% or more in comparison to the pre-treatment score (responders, n = 5; non-responders, n = 5). Pre- and post-treatment SIGH-SAD scores and SPET data were compared in each patient. An improvement in depressive symptoms after light therapy was associated with an increase in rCBF in the frontal and cingulate regions as well as the thalamus. Such changes were not seen in non-responsive subjects.

Adult↗
PubMed1996

Routine perioperative dipyridamole 201Tl imaging in diabetic patients undergoing vascular surgery.

OBJECTIVE: To assess the utility of dipyridamole thallium testing in symptomatic and asymptomatic patients with diabetes undergoing vascular surgery. RESEARCH DESIGN AND METHODS: Dipyridamole 201Tl myocardial scintigraphy was performed preoperatively in 93 consecutive patients with diabetes undergoing peripheral vascular procedures. The utility of clinical and thallium variables in predicting cardiovascular complications was assessed. RESULTS: Two groups of patients were identified: group A (36 patients) without clinical evidence of cardiac disease and group B (57 patients) with clinical evidence of cardiac disease. Dipyridamole thallium scans were abnormal in 21 of 36 (58%) of group A patients compared with 53 of 57 (93%) of group B patients (P < 0.0001). Compared with group B patients with perfusion defects, group A patients with perfusion abnormalities tended to have fewer defects per scan (2.7 +/- 1.5 vs. 3.6 +/- 1.9, P = 0.05). No perioperative cardiac complications occurred in group A patients while perioperative cardiac complications occurred in 9 of 57 (16%, 95% CI 7-28%) group B patients (P = 0.01). For the entire study population, the complication rate was 10%. CONCLUSIONS: Diabetic individuals without clinical markers for coronary artery disease appear to be at low risk for adverse postoperative cardiac events after vascular surgery. Preoperative myocardial perfusion imaging may add little to cardiovascular risk assessment in this subgroup of patients with diabetes.

Aged↗
PubMed1995

Three genes and two isozymes: gene conversion and the compartmentalization and expression of the phosphoglycerate kinases of Trypanosoma (Nannomonas) congolense.

The glycosome, a microbody organelle found only in kinetoplastid protozoa, compartmentalizes the first six enzymes of glycolysis. In order to better understand the regulation and targeting of glycolytic enzymes in trypanosomes, we have cloned and analyzed the three genes of the phosphoglycerate kinase (PGK) complex of Trypanosoma (Nannomonas) congolense. The organization of the genes within the complex is similar to that of Trypanosoma brucei brucei. The nucleotide and amino-acid sequences, including those of the novel high-molecular-weight 56PGK, show substantial cross-species similarity. However, the two downstream genes, c1PGK and c2PGK, encode identical isozymes in T. congolense, while they encode distinct glycosomal and cytoplasmic isozymes in T. brucei. Western analysis also indicated that there are only two isozymes in T. congolense and that these are constitutively expressed. Differential digitonin solubilization of the trypanosomes indicated that 56PGK is primarily localized to the glycosome, as expected, and that c1/c2PGK is cytoplasmic. Northern analysis demonstrates that while 56PGK is constitutively expressed, c1PGK and c2PGK mRNAs are differentially expressed in the T. congolense developmental stages. This work demonstrates that T. congolense has only one PGK isozyme, 56PGK, that is predominantly localized in glycosomes.

Amino Acid Sequence↗
PubMed1995

The percutaneous absorption of hydroquinone (HQ) through rat and human skin in vitro.

Because of the potential for human contact with photographic developer solutions containing hydroquinone (HQ), the rates of percutaneous absorption of HQ through human stratum corneum and full-thickness rat skin have been measured in vitro using 5% aqueous solutions of HQ as the donor solutions. The studies were performed using infinite doses of aqueous solutions containing 14C-labeled HQ in Franz-type diffusion cells. The measured absorption rate (mean +/- S.D.) of HQ through human stratum corneum was 0.52 +/- 0.13 micrograms/cm2/h, while that for full-thickness rat skin was 1.1 +/- 0.65 micrograms/cm2/h. The ratio (rat/human) of the permeability constants (Kp) was 2.4. Using the definitions suggested by Marzulli et al. (1969) Toxicol. Appl. Pharmacol. Suppl. 3, 76-83, HQ would be classified as 'slow' with respect to its absorption through human stratum corneum.

Animals↗
PubMed1995

Somatostatin receptor imaging of neuroendocrine tumors with indium-111 pentetreotide (Octreoscan).

Somatostatin, a naturally occurring 14-amino acid peptide, can be thought of as an anti-growth hormone and functional down-regulator of sensitive tissue. Most neuroendocrine tumors seem to possess somatostatin receptors in sufficient abundance to allow successful scintigraphic imaging with radiolabeled somatostatin congeners. Several of these, including Indium-III-DTPA Pentetreotide (Octreoscan [Mallinckrodt Medical, St. Louis, MO]), which was approved for clinical use by the Food and Drug Administration in June 1994, have been of considerable value in scintigraphically identifying various neuroendocrine tumors. The Octreoscan compares favorably with other imaging modalities. The success of somatostatin receptor imaging in evaluating patients with suspected neuroendocrine tumors, including identifying otherwise radiographically occult lesions, has resulted in ranking somatostatin receptor imaging as the prime imaging procedure in patients with suspected neuroendocrine tumors at The Ohio State University.

Humans↗
PubMed1995

Prospective evaluation of viable myocardium by quantitative dipyridamole-thallium-201 scintigraphy and radionuclide ventriculography.

Improvement of myocardial function is a major goal of coronary revascularization. Considerable interest remains in the preoperative identification of viable myocardium. We examined 26 consecutive patients with left ventricular dysfunction undergoing coronary artery bypass grafting. Serial dipyridamole-thallium imaging and radionuclide ventriculography was performed preoperatively and postoperatively. The relationship between preoperative and postoperative thallium perfusion and segmental wall motion was analyzed. The mean preoperative ejection fraction was 32 +/- 9 (21 to 51%) and increased to 41 +/- 12 (17 to 67%) postoperatively (p > 0.01). Seventy-seven percent of patients improved their global ejection fraction postoperatively by > 5%. Thallium perfusion improved postoperatively in 84% of reversible defects vs 63% of partially reversible defects and 35% of fixed defects. Segments with either reversible or partially reversible thallium defects showed an improved postoperative wall motion in 71% and 68%, respectively. Postoperative wall motion improved in 43% of fixed defects. Overall, 67% of hypokinetic segments showed improved postoperative wall motion while only 29% of akinetic or dyskinetic segments improved postoperatively. Preoperative thallium redistribution coupled with preserved wall motion was predictive of improvement in wall motion was predictive of improvement in wall motion postoperatively and indirectly indicates myocardial viability. However, 43% of fixed defects also showed improved postoperative wall motion. A significant improvement in global ejection fraction was found and could be predicted by a linear regression analysis utilizing clinical and thallium parameters.

Aged↗
PubMed1994

Measurement of nuclear DNA modification by 32P-postlabeling in the kidneys of male and female Fischer 344 rats after multiple gavage doses of hydroquinone.

Oral administration of hydroquinone (HQ) to male Fischer 344 (F344) rats results in dose-related kidney toxicity beginning with mild enzymuria by 1 week, significant cell proliferation by 6 weeks, and nephropathy and an increase in the incidence of renal tubule adenomas after 2 years. Female F344 rats, B6C3F1 mice, Sprague-Dawley rats, dogs, and humans are resistant to the renal toxicity of HQ associated with repeated exposure. To determine the potential of HQ to induce covalent DNA adducts in the kidney, male and female F344 rats were given 0, 2.5, 25, or 50 mg/kg HQ by gavage for 6 weeks, and nuclear DNA isolated from kidneys was analyzed by the 32P-postlabeling assay. At 50 mg/kg, males, but not females, showed an increase in the rate of excretion of N-acetyl-beta-D-glucosaminidase, indicative of proximal tubular damage. Analysis of nuclear DNA preparations by the postlabeling assay showed that HQ does not produce covalent DNA adducts in the kidneys of male and female rats. The assay's lower limit of detection is 1 adduct in 10(9) to 10(10) DNA nucleotides. No treatment-related increases in background radioactivity levels on the chromatograms were seen at locations corresponding to the major in vitro adducts of HQ and p-benzoquinone. HQ treatment, however, resulted in the reduction of the levels of certain endogenous adducts (I-compounds), the biological significance of which is unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The contribution of immunization to economic development.

Immunization received intensive support during the 1980s in light of its demonstrable value, relatively low cost, and established infrastructure. The goal of universal childhood immunization was achieved in 1990 on the basis of a strategy of expanding coverage, technological improvements, and social mobilization. Although its impact is difficult to quantify precisely, the Expanded Programme on Immunization (EPI) has had significant positive effects on national and household economies as a result of the reduction of morbidity and mortality. It also has contributed to the development of the managerial and operational capacity of health systems and to the generation of widespread social and political support for health actions through a variety of different mechanisms. Priorities for the next decade include attention to policies to ensure the maintenance of high levels of coverage, continued technical development, and further strengthening of EPI planning and management.

Child Health Services↗