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Biomedical subjects

R L Carter

Publications and source records attributed to R L Carter.

245 records · Page 14Linked to original sources
PubMedDate not supplied

Framework invasion by laryngeal carcinomas.

The accuracy of standard clinical and radiologic methods in detecting invasion of the laryngeal framework or the presence of a transglottic tumor was examined by comparing clinical and pathologic findings in a series of 50 randomly selected laryngectomies for squamous carcinoma. Forty-two of the patients had received radiation therapy as primary treatment. The presence of pain referred to the ear immediately before laryngectomy indicated invasion of the laryngeal framework or spread into the extralaryngeal soft tissues in 11 of 12 patients. Transglottic tumors were correctly identified in 10 of 14 patients from laryngeal tomograms, but seven additional tumors were incorrectly designated as transglottic. Both transglottic tumors and infraglottic extension were seriously underdiagnosed by direct laryngoscopy. Framework invasion was seen to be a feature of transglottic tumors 2 cm or more in diameter. The morphology of this process is described. Limited follow-up has already shown a pattern of early recurrence, frequently as cervical node metastases, that is significantly more common in patients with framework invasion.

Adult↗
PubMedDate not supplied

Invasion of the mandible by squamous carcinomas of the oral cavity and oropharynx.

The radiologic and histologic features of mandibular invasion, and its clinical implications, are considered in a retrospective series of 111 patients with squamous carcinomas of the oral cavity and oropharynx treated by composite resection. Eighty percent of the entire group had either recurrent or advanced (T3, T4) local disease, and 33 patients (30%) had histologic evidence of mandibular invasion by tumor. Preoperative radiologic assessment was unreliable in cases in which infiltrating tumor was confined to the periosteum and superficial cortex-44% false negatives. The extent of bone invasion was found to correlate with the size of the tumor, but not with its histologic grade. The mandibular periosteum was not seen as a morphologically discrete "barrier" and infiltration occurred at various points along the mandibular body, mainly related to the course of the inferior dental canal. The gross and microscopic patterns of bone invasion appeared to be similar in irradiated and nonirradiated resections. The incidence and pattern of recurrent disease following composite resection was the same in the groups with and without mandibular invasion: in each group half the patients were dead from disease and one third alive and free of disease at 2 years. Mandibular invasion alone did not appear to influence prognosis in this series.

Adult↗
PubMedDate not supplied

Radioimmunoscintigraphy of squamous carcinomas of the head and neck.

A pilot study was carried out to assess the value of a radiolabeled antibody against epidermal growth factor receptor (EGFR1) in localizing tumors in patients with squamous carcinomas of the head and neck. Positive images of large tumours (greater than 3 cm diameter) were obtained in 8 of 11 patients after intravenous administration of 111indium-labeled EGFR1. Two patients gave equivocal results, while negative scans were obtained from the patient with the smallest tumor (1 cm diameter). There were no false-positive images. The success of this study in localizing relatively large squamous carcinomas indicates that the antibody should be evaluated in patients with smaller tumors to establish the limits of detection of the technique.

Adult↗
PubMedDate not supplied

Effect of pollution on genetic diversity in the bay mussel Mytilus galloprovincialis and the acorn barnacle Balanus glandula.

To test if environmental contamination acts as a selection force affecting genetic diversity at the population level, two intertidal invertebrate species, Mytilus galloprovincialis and Balanus glandula, were collected from seven different bay sites in southern California. Collections were made at three relatively pristine 'clean' sites and four 'impacted' sites exposed to heavy industrial or boating activity, and which had previously been identified as having measurable levels of pollution. Genetic diversity at each site was assessed by comparing fragment polymorphisms generated from genomic DNA by randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). All populations retained a large amount of genetic diversity and were genetically similar to each other. However, several different measures of diversity indicated that, for most primers, the populations of both species from impacted sites had lower genetic diversity compared to those populations from clean sites. Individuals at impacted sites were more likely to share the same haplotypes than were those from clean sites. Few bands seen in the clean sites were absent from the impacted sites or vice versa, but a number of bands in the clean site populations were significantly less common in the impacted populations, while a few bands uncommon in clean site populations were more common at impacted sites. Together, these results suggest that pollution at the impacted sites may reduce genetic diversity among the resident invertebrate populations.

Animals↗
PubMedDate not supplied

Cytoplasmic male sterility in sunflower: origin, inheritance, and frequency in natural populations.

Cytoplasmic male sterility (CMS) in commercial sunflower hybrids is thought to be derived from a related wild species, Helianthus petiolaris, yet CMS lines are known to carry the chloroplast DNA genotype of H. annuus. To clarify the origin of sunflower CMS, we developed a polymerase chain reaction-based strategy for detecting CMS in sunflower and surveyed more than 1,200 plants representing 55 accessions of H. annuus and 26 accessions of H. petiolaris. We also tested 160 progeny from three crosses for strict maternal inheritance of organelle DNAs to determine if the apparent discrepancy in the species donor of the mitochondrial DNA and chloroplast DNA genotypes in CMS lines might result from low-frequency maternal or biparental inheritance of either organelle. No CMS cytotypes were observed in natural populations of either H. annuus or H. petiolaris, and strict maternal inheritance of organelle DNA was observed. These data provide little insight, therefore, into the origin and population genetics of CMS in natural populations of sunflower, except that the evidence for strict maternal inheritance of organelles in sunflower makes it unlikely that the mtDNA and cpDNA genotypes in CMS lines were derived from different species. Nonetheless, the primers developed for assaying organelle DNA variation in sunflower may be useful tools for plant breeding programs, cytotype identification, and systematic and evolutionary studies in the domesticated sunflower and its relatives.

Base Sequence↗
PubMedDate not supplied

Effect of reproductive status on feline renal size.

Renal length and width dimensions were determined from survey radiography and excretory urography in 28 cats of various sex and reproductive status. Renal dimensions were expressed as a ratio to the length of the second lumbar vertebra. Renal dimensions were not significantly different when males were compared to females. However, significant differences in renal dimensions between intact and neutered cats were identified. Renal length ratios for neutered cats were: left kidney 2.22 +/- 0.14 (mean +/- standard deviation), right kidney 2.29 +/- 0.14. In intact cats, renal length ratios were: left kidney 2.60 +/- 0.19, right kidney 2.65 +/- 0.24. The mean renal length ratios for neutered cats was smaller than previously reported normal values. Thus, reproductive status should be considered when evaluating feline kidneys for alterations in size. Based on this study, normal feline renal length ratios range from 1.9 to 2.6 for neutered cats and 2.1 to 3.2 for intact cats.

Animals↗
PubMedDate not supplied

Effects of changing therapy on cognition of children in renal failure.

To assess the effects of changing therapy for treatment of chronic renal failure on cognitive function, 56 renal failure children were matched to healthy control subjects. Neuropsychological tests were administered every 6 months for up to four testing sessions. The renal subjects had reduced function on medical management, were being dialyzed or had transplants. Those renal patients who changed treatment groups over the course of the study were classified as good or bad change depending upon medical criteria. Those patients who remained in the same treatment group were classified as no change. Differences in performance between last and first sessions were analyzed for each pair. Renal subjects exhibited less improvement on memory function than controls but greater improvement on choice reaction time and vigilance. Renal subjects making a good change did not exhibit significantly greater improvement than other groups on neuropsychological tests.

Adolescent↗
PubMedDate not supplied

Serial hippuran renograms to detect the late onset of renal allograft rejection in pediatric transplant recipients.

Serial hippuran renograms were performed in pediatric allograft recipients in an effort to detect the onset of rejection following the initial 3 month post transplant period. The plots of the normalized effective renal plasma flows (NERPF) were compared with reciprocal of the serum creatinines. A strong correlation was noted between both values. NERPF could be predicted from the serum creatinine utilizing a logarithmic equation. However, there was no detectable difference between the onset of changes in the slopes of either variable. Therefore, serial hippuran renograms were no better than monitoring serum creatinine in detecting allograft dysfunction when performed at the frequency of the study.

Adolescent↗
PubMedDate not supplied

Metastatic potential of malignant tumours.

The term 'metastatic potential' is examined, together with some of the factors that may contribute to it. The evidence is drawn from clinical and experimental sources. Morphological factors include the site of the tumour, its size, histological appearances and pattern of local spread. The scope and limitations of each are discussed and the potential application of newer morphological techniques is noted. Certain non-morphological factors are considered: these are (1) the functional heterogeneity of tumour cell populations with resepct to the metastatic capacity; (2) the elaboration of certain tumour-associated products which may potentiate tumour spread; and (3) immunological factors in the form of local host cell infiltrates in and around primary tumours. The tumour-associated products include collagenases, prostaglandins and angiogenesis factor; their likely origin from tumour and host cells is stressed, together with their implications in physiological and pathological processes other than neoplasia. It is concluded that the metastatic potential of tumours cannot be assessed in the terms of conventional tumour pathology alone. A more functional approach is needed before the term 'metastatic potential' acquires solid conceptual or practical value.

Angiogenesis Inducing Agents↗
PubMedDate not supplied

An immunocytochemical study of the distribution of epithelial membrane antigen in normal and disordered squamous epithelium.

Using immunocytochemical techniques, we have investigated the distribution of epithelial membrane antigen (EMA) in human squamous epithelium. The antigen is not demonstrable in normal adult tissues although it is present on the surface membrane of normal foetal epidermis before keratinization takes place. It may be expressed strongly in the adult, however, in in situ and infiltrative squamous carcinomas as well as in a variety of non-neoplastic states. Present evidence suggests that EMA may protect exposed surfaces. The lack of demonstrable antigen on malignant melanomas and basal cell carcinomas highlights the histogenetic differences between these tumours and squamous carcinomas, and suggests a possible role for EMA in the differential diagnosis of malignant skin tumours.

Antigens, Surface↗