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T L Gustafson

Publications and source records attributed to T L Gustafson.

At least 19 recordsLinked to original sources
PubMed2001

Photosystem II peripheral accessory chlorophyll mutants in Chlamydomonas reinhardtii. Biochemical characterization and sensitivity to photo-inhibition.

In addition to the four chlorophylls (Chls) involved in primary charge separation, the photosystem II (PSII) reaction center polypeptides, D1 and D2, coordinate a pair of symmetry-related, peripheral accessory Chls. These Chls are axially coordinated by the D1-H118 and D2-H117 residues and are in close association with the proximal Chl antennae proteins, CP43 and CP47. To gain insight into the function(s) of each of the peripheral Chls, we generated site-specific mutations of the amino acid residues that coordinate these Chls and characterized their energy and electron transfer properties. Our results demonstrate that D1-H118 and D2-H117 mutants differ with respect to: (a) their relative numbers of functional PSII complexes, (b) their relative ability to stabilize charge-separated states, (c) light-harvesting efficiency, and (d) their sensitivity to photo-inhibition. The D2-H117N and D2-H117Q mutants had reduced levels of functional PSII complexes and oxygen evolution capacity as well as reduced light-harvesting efficiencies relative to wild-type cells. In contrast, the D1-H118Q mutant was capable of near wild-type rates of oxygen evolution at saturating light intensities. The D1-H118Q mutant also was substantially more resistant to photo-inhibition than wild type. This reduced sensitivity to photo-inhibition is presumably associated with a reduced light-harvesting efficiency in this mutant. Finally, it is noted that the PSII peripheral accessory Chls have similarities to a to a pair of Chls also present in the PSI reaction center complex.

Animals↗
PubMed2000

Practical risk-adjusted quality control charts for infection control.

BACKGROUND: Control chart methodology has been widely touted for monitoring and improving quality in the health care setting. P charts and U charts are frequently recommended for rate and ratio statistics, but their practical value in infection control may be limited because they (1) are not risk-adjusted, and (2) perform poorly with small denominators. The Standardized Infection Ratio is a statistic that overcomes both these obstacles. It is risk-adjusted, and it effectively increases denominators by combining data from multiple risk strata into a single value. SETTING: The AICE National Database Initiative is a voluntary consortium of US hospitals ranging in size from 50 to 900 beds. The infection control professional submits monthly risk-stratified data for surgical site infections, ventilator-associated pneumonia, and central line-associated bacteremia. METHODS: Run charts were constructed for 51 hospitals submitting data between 1996 and 1998. Traditional hypothesis tests (P values <.05) flagged 128 suspicious points, and participating infection control professionals investigated and categorized each flag as a "real problem" or "background variation." This gold standard was used to compare the performance of 5 unadjusted and 11 risk-adjusted control charts. RESULTS: Unadjusted control charts (C, P, and U charts) performed poorly. Flags based on traditional 3-sigma limits suffered from sensitivity <50%, whereas 2-sigma limits suffered from specificity <50%. Risk-adjusted charts based on the Standardized Infection Ratio performed much better. The most consistent and useful control chart was the mXmR chart. Under optimal conditions, this chart achieved a sensitivity and specificity >80%, and a receiver operating characteristic area of 0. 84 (P <.00001). CONCLUSIONS: These findings suggest a specific statistic (the Standardized Infection Ratio) and specific techniques that could make control charts valuable and practical tools for infection control.

Bacteremia↗
PubMed1996

Influence of core fucosylation on the flexibility of a biantennary N-linked oligosaccharide.

Fluorescence energy transfer was used to study the conformation of each antenna of a complex biantennary oligosaccharide. A core fucosylated biantennary oligosaccharide was converted to a glycosylamine which allowed coupling of a naphthyl donor fluorophore directly to the reducing-end GlcNAc 1. After generating an aldehyde at C-6 of residue 6 or 6' using galactose oxidase, a dansyl ethylenediamine acceptor fluorophore was coupled to either antenna of the oligosaccharide resulting in two donor-acceptor pairs. [Formula: see text] The fluorescence properties of the naphthyl group allowed determination of the end-to-end donor-acceptor distance and antenna flexibility of each isomer by steady-state and time-resolved fluorescence energy transfer at temperatures ranging from 0 to 40 degrees C. Extended (20.6 A) and folded (11.4 A) donor-acceptor distance populations were identified for the isomer containing dansyl attached to Gal 6', whereas only a single extended population (19.7 A) was determined when dansyl was attached to Gal 6. The presence of Fuc 1' had a dramatic effect on the conformation of the 6' antenna. Temperature modulation failed to alter the ratio of extended/folded populations when fucose was present. However, following the removal of fucose, the ratio of the extended/folded populations for 6' exhibited a temperature dependent conformational equilibrium allowing calculation of the enthalpy and entropy of unfolding. These results established a unique conformational property for the 6' antenna of a biantennary oligosaccharide that is influenced by core fucosylation. Comparison of the results obtained for the 6 antenna of biantennary with previous fluorescence energy transfer studies on a triantennary glycopeptide also established conformational differences in this antenna which are dependent on oligosaccharide structure.

Carbohydrate Sequence↗
PubMed1993

Comparative study of the interactions of cisplatin and carboplatin with nucleotides using UV resonance Raman spectroscopy.

We have obtained the UV excited resonance Raman spectra of five mononucleotides bound to cisplatin and to carboplatin using excitation in resonance with the first electronic absorption bands of the nucleotide bases. Substantial changes in the spectra are observed following interaction with both platinum drugs, indicating modifications to nucleotide structure. Pt (II) binds to base portions of the nucleotide molecules, altering their normal modes of vibration significantly. We present comparative data of cisplatin and carboplatin, and discuss the implications of these results. The kinetics of the drug/nucleotide reactions differ, but final products are found to be similar.

Carboplatin↗
PubMed1987

Measles outbreak in a fully immunized secondary-school population.

An outbreak of measles occurred among adolescents in Corpus Christi, Texas, in the spring of 1985, even though vaccination requirements for school attendance had been thoroughly enforced. Serum samples from 1806 students at two secondary schools were obtained eight days after the onset of the first case. Only 4.1 percent of these students (74 of 1806) lacked detectable antibody to measles according to enzyme-linked immunosorbent assay, and more than 99 percent had records of vaccination with live measles vaccine. Stratified analysis showed that the number of doses of vaccine received was the most important predictor of antibody response. Ninety-five percent confidence intervals of seronegative rates were 0 to 3.3 percent for students who had received two prior doses of vaccine, as compared with 3.6 to 6.8 percent for students who had received only a single dose. After the survey, none of the 1732 seropositive students contracted measles. Fourteen of 74 seronegative students, all of whom had been vaccinated, contracted measles. In addition, three seronegative students seroconverted without experiencing any symptoms. We conclude that outbreaks of measles can occur in secondary schools, even when more than 99 percent of the students have been vaccinated and more than 95 percent are immune.

Adolescent↗
PubMed1987

Disease surveillance and emergency services at the 1982 World's Fair.

We designed a special surveillance system to detect health complaints of visitors to the 1982 World's Fair. Heat-related illness occurred during the first month of the Fair but was substantially reduced by public education, environmental modification, and provision of additional water fountains. There was no disruption of emergency health services in the communities surrounding the Fair. Advance planning and the provision of on-site medical services can minimize the public health impact of large gatherings.

Emergency Medical Services↗
PubMed1986

Contaminated produce--a common source for two outbreaks of Shigella gastroenteritis.

Simultaneous outbreaks of Shigella sonnei gastroenteritis occurred in October 1983 at two Texas university campuses 60 miles (96 km) apart. There were no common food handlers, recreational activities, water sources or swimming areas to explain the introduction of Shigella at both campuses. However, tossed salads were found to be associated with illness at both campuses. The investigation disclosed that both schools had received produce shipments from the same company during the week preceding these outbreaks. Shigella isolates from cases at both universities, sent to the Centers for Disease Control for plasmid analysis and colicin typing, were found to be identical. The same organism was evidently not a frequent cause of shigellosis within a 160-mile (256 km) radius of these universities since only 19% of control isolates chosen from this area were identical to the type which caused these outbreaks. This is the first report of two related outbreaks of shigellosis that were caused by a contaminated food source and not by a food handler. Simultaneous foodborne outbreaks of shigellosis should trigger a search for potential contamination at every step of food handling from farm to kitchen.

Disease Outbreaks↗
PubMed1985

A mysterious cluster of deaths and cardiopulmonary arrests in a pediatric intensive care unit.

In the period April 1981 through June 1982, there was an unusual increase in the number of deaths and cardiopulmonary arrests in the pediatric intensive care unit at a large medical center hospital in San Antonio, Texas. During this period, 34 of 42 deaths (81 per cent) occurred in the evening work shift, as compared with 36 of 106 (34 per cent) during the previous four years (P less than 0.0001). Reviews of records of patients revealed no association between death in this 15-month epidemic period and a variety of demographic, historical, medical, and admission characteristics; medical or surgical procedures; or the severity of illness. The findings of a blinded clinical consultant support the conclusion that the increase in deaths and cardiopulmonary arrests could not be explained on the basis of the clinical status of the patients, and the consultant concluded that during the epidemic period, there were more deaths and cardiopulmonary arrests that were either unexpected in timing or inconsistent with the previous clinical course. The presence of one nurse was associated with the increased numbers of deaths (relative risk, 10.7; 95 per cent confidence limits, 6.4 to 17.9), cardiopulmonary arrests (relative risk = 25.5, confidence limits = 16.8 to 38.6), and unexpected clinical events, (relative risk, infinite; confidence limits, 33.7 to infinity). Although the cause of the epidemic remains unclear, the findings illustrate that surveillance of deaths and cardiopulmonary resuscitation may allow early recognition of similar problems in other hospitals.

Child↗
PubMed1985

Antipyretic use among children during the 1983 influenza season.

We conducted a telephone survey in Houston in March 1983 to assess the level of aspirin use among children during the influenza season. We completed interviews of 200 households with 346 children aged 12 years or younger. Fifty-two percent of the 346 children experienced at least one acute illness in the preceding three months. Fever was measured with a thermometer in 114 ill children, 103 of whom had at least one measured temperature of 37.7 degrees C or greater. Fourteen percent of these 103 children received aspirin only, 61% received acetaminophen only, and 20% received both. Among a subgroup of 44 children with temperatures of at least 39.4 degrees C, 11% received aspirin only, 59% received acetaminophen only, and 27% received both. Only 60% of the 200 parents interviewed had heard of Reye's syndrome. Forty-two percent knew of the association between Reye's syndrome and aspirin use. The survey suggests that acetaminophen has replaced aspirin as the major antipyretic used by children in Houston. If the decline in aspirin use in Houston is representative of the population in the United States, and if aspirin is causally related to Reye's syndrome, the incidence of Reye's syndrome may decline.

Acetaminophen↗
PubMed1985

Cryptosporidiosis outbreak in a day-care center.

An outbreak of diarrhea occurred in a day-care center in San Marcos, Tex, in August 1984. At the time of this study, the center was caring for 81 children aged 2 months through 5 years. A single stool specimen was collected from each of 50 children (62%). Cryptosporidium oocysts and Giardia lamblia cysts were each identified in stool specimens from 18 children. Three children had both parasites present in the same stool specimen. Echovirus 30 was identified in 19 of 25 stools cultured. Although three pathogens were circulating simultaneously in this group of children, only the presence of Cryptosporidium oocysts was associated with the occurrence of a diarrheal illness. Cryptosporidium may be a common cause of diarrhea in children who attend day-care centers.

Animals↗
PubMed1985

A cluster of true appendicitis cases.

A cluster of cases of appendicitis occurred primarily in school-age boys in a small Texas town. The expected rate of appendicitis is 1.5 cases per 1,000 persons, or about 1 case per month in that town. However, in the spring of 1984, 13 cases, 10 in school-age boys, occurred. In eight of these patients, the initial onset of abdominal pain occurred over a 15 day period. A case controlled study of school-age patients indicated that sweets in the diet and consumption of local farm eggs may have been associated with the appendicitis. We hypothesize that a group of young male patients who were susceptible to appendicitis because of the high sugar content of their diets were exposed to a bacterium or virus that precipitated this outbreak of appendicitis.

Acute Disease↗
PubMed1985

Clinical aspects of cutaneous leishmaniasis acquired in Texas.

Five patients with cutaneous leishmaniasis are described. Four of these patients acquired leishmaniasis in Texas. Four cases represent acute cutaneous leishmaniasis, and one case probably represents chronic cutaneous leishmaniasis. The classification and treatment of cutaneous leishmaniasis are reviewed. One patient in this report was successfully treated with topical antimony cream. Cutaneous leishmaniasis must be considered in the differential diagnosis of nonhealing ulcerated papules and nodules even in patients who do not have a foreign travel history.

Acute Disease↗
PubMed1985

An outbreak of invasive aspergillosis among allogeneic bone marrow transplants: a case-control study.

Between April 1982 and March 1983, 10 of 26 (38.4%) allogeneic bone marrow transplant recipients housed on a newly opened bone marrow transplant unit developed invasive aspergillosis. By contrast, between September 1977 and March 1982, only 3 of 46 (6%) transplant recipients developed invasive aspergillosis. A case-control study to identify host factors related to Aspergillus infection found that aspergillosis was more common in patients with chronic myelogenous leukemia and aplastic anemia, older patients, patients having cytomegalovirus disease, patients who experienced prolonged granulocytopenia, patients conditioned with ara-C (100-200 mg/day), and patients who received longer duration of antimicrobial therapy. A series of logistic regression analyses revealed that underlying disease was the single best predictor of Aspergillus infection. This study demonstrates that underlying disease is an important risk factor for aspergillosis and that special measures may be warranted when transplanting certain patients.

Adult↗
PubMed1985

Human cutaneous leishmaniasis acquired in Texas.

Four cases of autochthonous human cutaneous leishmaniasis have been identified in south-central Texas since 1980. The patients presented with chronic ulcerating papules on the face, earlobe, and lateral thigh. In two patients, the infections healed without treatment. In the other two patients, the lesions healed following treatment with intramuscular sodium stibogluconate or topical antimony potassium tartrate. Serologic testing of family members, using four different techniques, indicates that asymptomatic infections may occur. These are the first reported cases of cutaneous leishmaniasis acquired in Texas since 1974. Organisms isolated from patients in 1974 and 1980 belonged to the Leishmania mexicana complex when tested by the isoenzyme technique. Although no animal reservoir or insect vector has been identified, six species of sand flies belonging to the genus Lutzomyia do inhibit this part of Texas. Accumulated evidence strongly suggests that cutaneous leishmaniasis is endemic in south-central Texas.

Antibodies↗
PubMed1985

A waterborne outbreak of cryptosporidiosis in normal hosts.

In July 1984, an outbreak of gastroenteritis occurred in a suburban community in Texas. A random telephone survey of 100 of 1791 households in the community identified an attack rate of 34%. The outbreak was traced to contamination of the community water supply, an artesian well. Fecal coliforms were identified in untreated drinking water from the well during July. Stool examinations and serologic tests identified Cryptosporidium as the etiologic agent. Cryptosporidium should be added to the list of waterborne organisms capable of causing outbreaks of gastroenteritis.

Adolescent↗
PubMed1984

Outbreak of varicella in a newborn intensive care nursery.

An outbreak of nosocomial varicella occurred in the neonatal intensive care unit of a west Texas hospital in 1982. Two health care workers and two infants were infected. The two infants acquired varicella following intimate exposures, although their mothers were shown to be seropositive. One of these infants had varicella-zoster antibody when exposed, received varicella-zoster immune globulin, and still had chickenpox develop. Thus, the presence of varicella-zoster antibody may not prevent infection in infants.

Chickenpox↗