Biomedical subjects
Publications and source records attributed to J Lynch.
A case of a short above-knee amputation stump closed with a rectus abdominis musculocutaneous flap is presented. This single-stage procedure provided soft-tissue coverage for the above-knee amputated stump, promoted early ambulation, and preserved bone length.
Five triorganotin 5-nitro-2-furoates were synthesized by reacting 5-nitro-2-furoic acid with either the corresponding bis(triorganotin) oxide or the corresponding triorganotin hydroxide. The IR spectrum of each compound was obtained over the 4000--200-cm-1 range, and some of the bands were assigned. One compound, tri-n-butyltin 5-nitro-2-furoate, was an excellent antifungal agent, completely inhibiting the growth of six of ten test fungi at a concentration of 1 microgram/ml. The new compounds were also investigated for antibacterial activity and were especially inhibitory toward Gram-positive species. Two of the compounds completely inhibited the Gram-negative bacterium Escherichia coli at a concentration of 100 microgram/ml.
While the etiology of bronchogenic carcinoma remains enigmatic, an expanding array of carcinogenic pollutants in interaction with host susceptibility factors has been implicated. We have studied family histories of cancer in a consecutive series of cancer patients from two university oncology clinics in Nebraska. Particular attention has been given to carcinoma of the lung and other putative smoking-associated cancers (oral cavity, esophagus, urinary bladder, pancreas). Smoking histories were obtained for relatives of an overlapping series of patients with these tumor sites. Findings revealed that, although a significant cohort effect was observed with respect to smoking habits for both relatives of lung cancer probands and for relatives of probands with other smoking-associated tumors, a corresponding trend for lung cancer frequency was observed only for relatives of lung cancer probands. This result suggests the importance of host factors in combination with environmental exposures in determining lung risk. A cohort trend for lung cancer was also apparent among relatives of breast cancer probands, but not for relatives of colon cancer probands, suggesting the possibility of an intrinsic association between carcinomas of the breast and lung. We believe that further elucidation of host factor susceptibility in lung cancer may have important etiological and preventive implications.
A porcine parvovirus has been characterized with regard to its replication in foetal porcine kidney cells and certain biophysical properties. Electron microscopy of infected cells at selected times postinfection revealed that porcine parvovirus replication took place within or near a series of granular intranuclear inclusions which may be contiguous with cellular heterochromatin. Developing virions were observed to aggregate into a nucleolar-like amorphous mass which gradually disrupted as cellular integrity was lost. Purified virions were found to have a buoyant density in CsCl of 1.38 g/ml, while 'empty' particles had a buoyant density of 1.29 g/ml. The particle diameter was calculated to be approximately 22 nm.
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Escherichia coli 16S RNA from 30S ribosomal subunits was isolated, oxidized at the 3' end, and labeled with the thiosemicarbazide derivatives of fluorescein or eosin. Labeled 16S RNA was reconstituted into 30S subunits. They were almost fully active compared to 30S subunits reconstituted from unlabeled 16S RNA by using a poly(uridylic acid)-directed polyphenylalanine synthesis assay. Fluorophores were placed at three different positions of tRNAPhe. E. coli and yeast tRNAPhe were oxidized at the 3' end and labeled with the thiosemicarbazide derivative of fluorescein or with the hydrazide of N-methylanthranilic acid. The Y base in the anticodon loop of yeast tRNAPhe was replaced by proflavin or 1-aminoanthracene. Also, E. coli tRNAPhe was photochemically cross-linked between 4-thiouridine at position 8 and cytidine at position 13. After reduction, this site was used as a fluorescent probe. The labeled tRNAs were bound into the peptidyl site of 70S ribosomes, and then the distances from the fluorophore in the modified tRNA to the fluorophore at the 3' end of 16S RNA were measured by nonradiative energy transfer. Calculations were based on measurements of fluorescence lifetimes. The distances to the 3' end of 16S RNA were found to be as follows: 3' end of tRNA, 67-74 A; cross-linked t RNA, 53-60 A; anticodon loop of tRNA, greater than 61 A.
Knowledge of cancer genetics provides the physician with a powerful tool for the recognition of patients who might profit from highly targeted cancer surveillance/management programs. Family history was evaluated by registered nurses on 565 consecutively ascertained patients with verified cancer from Creighton's Oncology Clinic. This initial assessment yielded 199 (35.5%) families with two more family members with cancer (all sites) within an informative nuclear component, which constituted parents, grandparents, aunts/uncles, siblings, and children. One or more of the operational criteria for cancer familiality, namely vertical transmission of cancer, bilaterality, and/or multiple primaries, early age of onset, and three or more site specific cancers, were found on physician review in 171 (30.5%) of the families. This group was referred for comprehensive cancer genetic evaluation consisting of pedigree extension and tumor verification through all second degree, and when possible, third degree relatives. It was determined that approximately 4% of the total clinic population demonstrated findings compatible with hereditary cancer syndromes. Its universal extension in clinical practice is advocated because of the potential yield from meticulous surveillance for cancer of highly targeted organs in such high-risk kindreds, as well as the economy and general case of obtaining detailed family history by registered nurses. The physician is able, therefore, to devote his primary effort toward pedigree analysis and syndrome identification.
Diurnal glucose profiles have been compared in ten insulin dependent diabetics receiving, firstly, a twice-daily soluble insulin (SI): isophane insulin (NPHI) insulin (30% SI, 70% NPHI). For each patient the two regimens gave similar profiles though nocturnal blood glucose control was better on Mixtard. HbA1 values were similar on the two regimens. The findings show that, using highly purified formulations, small changes in insulin proportions in twice-daily SI: NPHI regimens may be irrelevant to diabetic control; they also suggest that highly purified NPHI may have a substantially shorter duration of action than its older counterpart and that the convenient regimen of twice-daily Mixtard is usually as good as any more complicated 'tailormade' regimen of highly purified insulins.
The three ribonucleic acids (RNAs) from Escherichia coli ribosomes were isolated and then labeled at their 3' ends by oxidation with periodate followed by reaction with thiosemicarbazides of fluorescein or eosin. Ribosomal subunits reconstituted with the labeled RNAs were active for polyphenylalanine synthesis. The distances between the 3' ends of the RNAs in 70S ribosomes were estimated by nonradiative energy transfer from fluorescein to eosin. The percentage of energy transfer was calculated from the decrease in fluorescence lifetime of fluorescein in the quenched sample compared to the unquenched sample. Fluorescence lifetime was measured in real time by using a mode-locked laser for excitation and a high-speed electrostatic photomultiplier tube for detection of fluorescence. The distances between fluorophores attached to the 3' ends of 16S RNA and 5S RNA or 23S RNA were estimated to be about 55 and 71 A, respectively. The corresponding distance between the 5S RNA and 23S RNA was too large to be measured reliably with the available probes but was estimated to be greater than 65 A. Comparison of the quantum yields of the labeled RNAs free in solution and reconstituted into ribosomal subunits suggests that the 3' end of 16S RNA does not interact appreciably with other ribosomal components and may be in a relatively exposed position, whereas the 3' ends of the 5S RNA and 23S RNA may be buried in the 70S ribosomal subunit.
Benzene is a major commodity chemical of great value to industry. It has long been recognized that overexposure to benzene could result in damage to the blood-forming organs of the body. More recently, it has become apparent that chronic high levels of exposure are associated with the development of leukemia. Animal experiments have also suggested that overexposure to benzene may result in certain reproductive risks.
An effective strategy to prevent health hazards will utilize industrial hygiene principles in all phases of a project, including process development, the design bases, the final design, during construction, and during and after start-up. The involvement of industrial hygiene in engineering design results in cost-effective minimization of health hazards from toxic chemicals and harmful physical agents. Measurements of post start-up emission levels and employee exposures can be utilized to evaluate the performance of the controls which were implemented in the design. This will aid in the development of future designs and identify where research is needed to develop better controls to prevent health hazards.
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A morbidity and mortality study of workers at an alcohol manufacturing plant which included several weak acid isopropyl alcohol units and a strong acid ethanol unit is described. An excess mortality of upper respiratory cancer was found and associated with work on the strong acid ethanol unit. The strong acid ethanol process used resulted in high concentrations of diethyl sulfate, which has been shown to be carcinogenic in animals, and the unit, which closed on 1975, had significant opportunities for worker exposure to diethyl sulfate. These facts, plus previous reports of excess upper respiratory cancer on strong acid isopropyl alcohol units with similarly high concentrations of the animal carcinogen diisopropyl sulfate, lead to the tentative conclusion that diethyl sulfate was primarily responsible for the ethanol unit cancer cases. In the modern weak acid isopropyl alcohol plants, where only trace amounts of diisopropyl sulfate are present and exposures are much lower, the problems found on the old strong acid units do not exist.
Industrial hygiene engineering can be utilized most effectively when it is employed in the design or construction phases of new or modified chemical manufacturing processes. Minimization of leaks, spills, fugitive emissions and other releases is the goal. Some chemical and physical agents can still be released during normal or non-normal operations and during plant turnaround procedures and these require continuous industrial hygiene surveillance. It follows that industrial hygiene principles must continue to be applied in all phases of the petrochemical industry from the beginning of the design and throughout the life of the unit.
The literature suggests that cleft palate children and adults perform below their peers on both linguistic and nonlinguistic tasks. The purpose of this investigation was to ascertain if developmental delay could be observed in 24 cleft palate children below the age of three years when compared to matched controls. Three developmental scales were administered to all infants, and complete medical histories and current weights were obtained. Results indicated that the performance of the cleft palate subjects paralleled but fell below their peers on all developmental subtests. The differences were significant (p is less than .05) on three language subtests and on one personal-social and one motor subtest. The mean percentile weight also differed significantly (p is less than .05). Multivariate analysis explored the relationship of 1) extent of cleft, 2) sex, 3) hearing loss, 4) length of hospitalization, and 5) weight to the developmental scores. The extent of the cleft proved to be significant.
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Information requests received over a 14-month period in the drug information service of an oncology hospital were reviewed. Requests were classified as to the nature of the question, category of requestor and geographical distribution of both questions and requestors. Inquiries were tabulated as either oncology-related or nononcology and further divided into one of 12 information categoreis. Those questions concerning investigational chemotherapy and unproven cancer remedies were tabulated. An average of 104 requests monthly were received. Prescribing practitioners accounted for 47.7% of all inquirers. Overall, 39.4% of total requests were oncology-related. The majority (72%) of total requests originated within the institution. The greatest number of requests (17.7%) were of a general review nature. The second greatest number (14.3%) were efficacy-related questions which solicited an opinion as to the appropriateness of drug use. Methods need to be developed for measuring the impact of drug information services on prescribing habits.