Search PubMed⌕ Search

Biomedical subjects

K Patterson

Publications and source records attributed to K Patterson.

At least 19 recordsLinked to original sources
PubMed1992

Regional response differences within the human auditory cortex when listening to words.

The relationship between activity within the human auditory cortices and the presentation rate of heard words was investigated by measuring changes in regional cerebral blood flow with positron emission tomography. We demonstrate that in the primary auditory cortices and middle regions of the superior temporal gyri there is a linear relationship between the rate of presentation of heard words and blood flow response. In contrast, the blood flow response in an area of the left posterior superior temporal gyrus (Wernicke's area) is primarily dependent on the occurrence of words irrespective of their rate of presentation. The primary auditory cortices are associated with the early processing of complex acoustic signals whereas Wernicke's area is associated with the comprehension of heard words. This study demonstrates for the first time that time dependent sensory signals (heard words) detected in the primary auditory cortices are transformed into a time invariant output which is channelled to a functionally specialised region--Wernicke's area. Wernicke's area is therefore distinguished from other areas of the auditory cortex by direct observation of signal transformation rather than by association with a specific behavioural task.

Adult↗
PubMed1992

Solitary thyroid nodules in 71 children and adolescents.

Seventy-one children and adolescents with a solitary nodule of the thyroid gland were seen over a 27-year period and all had their nodules removed surgically. All of the patients had preoperative thyroid scintiscans, 55 of which showed a cold nodule. The most common cause of solitary thyroid nodules was follicular adenoma. Fourteen of the 55 cold nodules were malignant (25.5%) while no malignancies were present in warm or hot nodules. Available diagnostic methods for attempting differentiation of benign from malignant solitary nodules are reviewed and recommendations to their clinical management as derived from our experience are presented.

Adolescent↗
PubMed1992

Primary (retractile) mesenteritis in a child.

We report a case of primary retractile mesenteritis presenting as acute abdominal pain requiring surgery in a 3-year-old boy. At laparotomy, a hemoperitoneum was discovered and the diagnosis of primary mesenteritis was made with the aid of frozen section biopsy of the small bowel mesentery. No resection was necessary, and he made an uneventful recovery and remains well on follow-up.

Child, Preschool↗
PubMed1992

Deterioration of word meaning: implications for reading.

We investigated six patients with progressive focal dementia or progressive aphasia, who showed impairments in knowledge of word meaning ranging from moderate to very severe. In all cases, a test of oral word reading demonstrated preserved reading of words with regular spelling-to-sound correspondences (e.g. MINT), but impaired reading of words with atypical correspondences (e.g. PINT). The level of success on these "exception" words was significantly related to word frequency, and the most common error was the assignment of a more typical spelling-sound correspondence. Various explanations are considered for this common association between loss of word meaning and a surface alexic pattern of reading performance.

Aged↗
PubMed1992

The cortical localization of the lexicons. Positron emission tomography evidence.

Positron emission tomography was used to investigate changes in regional cerebral blood flow (rCBF) in neurologically normal subjects during word reading and word repetition. The blood flow in these conditions was compared with control conditions where subjects were presented with stimuli of comparable auditory and visual complexity to real words and said the same word on presentation of each stimulus. The control condition for word repetition (hearing spoken words presented backwards) resulted in bilateral activation of the superior temporal gyrus. Word repetition caused a significant increase in rCBF over this control condition in the left superior and middle temporal gyri. The control condition for word reading (seeing stimuli written in 'false fonts', i.e. non-existent letter-like forms) resulted in significant changes in rCBF bilaterally in the striate and extrastriate cortex. Word reading caused a significant increase in blood flow relative to this control in the posterior part of the left middle temporal gyrus. The implications of these results are discussed, and it is argued that they are consistent with localization of a lexicon for spoken word recognition in the middle part of the left superior and middle temporal gyri, and a lexicon for written word recognition in the posterior part of the left middle temporal gyrus.

Adult↗
PubMed1992

Semantic dementia. Progressive fluent aphasia with temporal lobe atrophy.

We report five patients with a stereotyped clinical syndrome characterized by fluent dysphasia with severe anomia, reduced vocabulary and prominent impairment of single-word comprehension, progressing to a stage of virtually complete dissolution of the semantic components of language. A marked reduction in the ability to generate exemplars from restricted semantic categories (e.g. animals, vehicles, etc.) was a consistent and early feature. Tests of semantic memory demonstrated a radically impoverished knowledge about a range of living and man-made items. In contrast, phonology and grammar of spoken language were largely preserved, as was comprehension of complex syntactic commands. Reading showed a pattern of surface dyslexia. Autobiographical and day-to-day (episodic) memory were relatively retained. Non-verbal memory, perceptual and visuospatial abilities were also strikingly preserved. In some cases, behavioural and personality changes may supervene; one patient developed features of the Kluver-Bucy Syndrome. Radiological investigations have shown marked focal temporal atrophy in all five patients, and functional imaging by single positron emission tomography and positron emission tomography (one case) have implicated the dominant temporal lobe in all five. In the older literature, such cases would have been subsumed under the rubric of Pick's disease. Others have been included in series with progressive aphasia. We propose the term semantic dementia, first coined by Snowden et al. (1989), to designate this clinical syndrome.

Adult↗
PubMed1992

Primary nasal chondrosarcoma. The pediatric experience.

Chondrosarcomas are infrequently found in the head and neck region. In a review of nonepithelial tumors of the nasal cavity, paranasal sinuses, and nasopharynx, only 4% were chondrosarcomas. The peak incidence occurs in the fourth decade of life. Only four cases of head or neck chondrosarcoma in children less than or equal to 10 years of age have been described in the literature, and only two of these were primary nasal cavity tumors. We present in this report a case of a 5-year-old boy treated with adjuvant chemotherapy after complete resection of a nasal cavity chondrosarcoma, and a review of the literature on this topic.

Age Factors↗
PubMed1992

Gaucher disease: abdominal MR imaging findings in 46 patients.

Abdominal magnetic resonance imaging findings were reviewed in 46 patients with Gaucher disease. All patients had hepatosplenomegaly at the time of initial imaging. Splenic nodules were present in 14 patients (30%) and varied in signal intensity. These nodules were isointense on T1-weighted and hypointense on T2-weighted images. Splenic infarcts were seen in 15 patients (33%), and four of these patients (9%) also had subcapsular fluid collections. Both nodules and infarcts were present in the spleen in four patients (9%). Pathologic correlation was performed with specimens from two patients who underwent partial splenectomy. Focal areas of abnormal signal intensity were noted in the liver in nine patients (20%). They were either stellate or segmental, and may represent fibrotic septa with ischemic changes associated with aggregates of Gaucher cells. No changes were noted in the kidneys or abdominal lymph nodes.

Adolescent↗
PubMed1992

Effects of temafloxacin and ciprofloxacin on the pharmacokinetics of caffeine.

A number of quinolone antibacterial agents, particularly enoxacin, pefloxacin, pipemidic acid and ciprofloxacin, are known to decrease the clearance of methylxanthines. The effects of temafloxacin and ciprofloxacin on the pharmacokinetics of caffeine were therefore compared in a 3-way crossover study in 12 healthy young volunteers. Each volunteer received 183mg once-daily doses of caffeine in conjunction with twice-daily placebo, temafloxacin 600mg and ciprofloxacin 750mg in 3 separate phases according to a randomised sequence. A doubling of the area under the plasma concentration-time curve (77.8 vs 31.8 mg/L.h) and terminal-phase half-life (9.7 vs 4.5h) of caffeine were observed in the presence of ciprofloxacin. The magnitude of the reduction in the intrinsic clearance of caffeine produced by ciprofloxacin was greater than that described in the literature for ciprofloxacin and theophylline. This may partly be explained by intertrial differences in dosage and study design. Coadministration of temafloxacin did not have any effect on the pharmacokinetics of caffeine, confirming results of other studies suggesting that this agent does not affect methylxanthine clearance. Accordingly, it appears that restriction of caffeine intake during temafloxacin therapy is not necessary.

Adult↗
PubMed1991

Language activation studies with positron emission tomography.

Behavioural tasks produce changes in regional cerebral blood flow (rCBF), the result of increased local neural activity. These changes can be measured with positron emission tomography (PET). Language activation studies by means of PET are being used to relate regional patterns of cerebral activation to information-processing models of speech and reading. Significant activation confined to both superior temporal gyri has been observed when normal subjects hear words played backwards, listen to non-words, and perform category judgements on pairs of heard real words. Prestriate cortex is activated by seeing strings of letter-like symbols, consonant strings, pronounceable non-words and real words, with additional activation in left medial prestriate cortex in response to the non-words and real words. Left posterior superior temporal gyrus (PSTG), left dorsolateral prefrontal cortex (DLPFC) and supplementary motor area (SMA) are engaged when subjects retrieve verbs from memory to match nouns. Finally, primary sensorimotor cortex is activated during articulation. There is particular interest at present in the precise roles of left PSTG and DLPFC in single-word comprehension and generation, and interpretation of the results depends critically on the design of the single-word tasks used for behavioural activation.

Aphasia↗
PubMed1991

Impact of two cycles of preoperative chemotherapy with intraarterial cisplatin and intravenous doxorubicin on the choice of surgical procedure for high-grade bone sarcomas of the extremities.

The authors assessed the impact of two cycles of preoperative chemotherapy (POCT) with intraarterial cisplatin (120 mg/m2) and continuous intravenous doxorubicin hydrochloride (Adriamycin; 20 mg/m2/day x 3 days) on the decision to perform a limb-sparing procedure (LSP) or amputation in 22 patients with high-grade bone sarcomas of the extremities. The tumor types were osteosarcoma (17), malignant fibrous histiocytoma (three), leiomyosarcoma (one), and malignant schwannoma (one). Surgical stages were IIA (three), IIB (17), and IIIB (two). The prechemotherapy surgical options chosen were 12 amputations (55% of patients) and ten LSPs (45%). The initial decisions to amputate were based on a combination of the following: improper biopsy (five cases), large tumors (ten) and those with neurovascular encroachment (six), and pathological fracture (one). Following chemotherapy, 18 LSPs (81%) and four amputations (19%) were performed. Nine of 12 patients (75%) initially deemed unresectable were converted to LSP. The median tumor response (necrosis; range, 0%-100%) was 70%; ten of 22 specimens had necrosis greater than 95%. Median tumor necrosis for the patients treated by amputation and LSPs was 45% and 88%, respectively. Following surgery, all patients received four additional cycles of cisplatin and doxorubicin. The median follow-up period is 30 months; six patients have developed metastatic disease, with a median disease-free interval of 16.6 months. The rate of local tumor control is 95% (21 of 22 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

A survey of antiemetic use in children with cancer.

Pediatric oncologists within Pediatric Oncology Group institutions were surveyed to determine current antiemetic practices for children receiving chemotherapy and the basis for those practices. A mean severity rating for associated nausea and vomiting was calculated and used to rank 31 chemotherapeutic agents commonly used in the treatment of childhood cancer. Antiemetics were used 17%, 79%, and 98% of the time for chemotherapeutic agents with mild, moderate, or severe associated nausea and vomiting, respectively. A median of one, two, and three antiemetics were used for mild, moderate, and severe agents, respectively. Antihistamines and phenothiazines were the drugs most commonly used for agents causing mild or moderate nausea and vomiting, and metoclopramide hydrochloride/antihistamines with lorazepam and/or corticosteroids were used most often for chemotherapeutic agents causing severe nausea and vomiting. Most oncologists based their choice of antiemetics on personal experience. Current literature addressing the treatment of nausea and vomiting in children receiving chemotherapy, as reviewed here, does not always support the present clinical practices.

Antiemetics↗
PubMed1990

Quantitative assessment of the rat stria vascularis.

Stria vascularis tissues from standardized regions in the basal, middle and apical turns of the rat cochlear duct were assessed quantitatively. Strial width, number of marginal cells across the strial width, radial area, as well as the volume density of the different components of the stria vascularis were determined for each standardized region. Strial width, number of marginal cells across the strial width and the radial area were greatest in the basal region and least in the apical region of the cochlea. The volume density of intermediate cells and capillary space was statistically unchanged in the three examined regions of the stria vascularis. However, the volume density of marginal cells and that of basal cells were different between regions. The volume density of marginal cells was highest in the basal turn while the volume density of basal cells was greatest in the apical turn. An objective assessment of the response of the stria vascularis to environmental conditions can be made by kant of its cellular architecture, providing a means to compare the effects of various agents between animal models used to study human inner ear dysfunction.

Animals↗
PubMed1990

Pulse oximetry as a means of assessing bowel viability.

Utilizing a pulse oximeter, oxygen saturation was determined in the periphery (tongue) and compared to the intestinal wall in a canine model. Segmental intestinal ischemia was then produced and the last obtainable pulse oximetry reading was marked with a suture on either end of the ischemic segment. Reexploration was performed within 48 hr and full thickness biopsies were taken in normal intestine and at various distances into the ischemic segment. Blinded evaluation of the biopsies showed that all biopsies taken within 1 cm of a normal pulse oximetry reading were normal, whereas at 3 cm into the ischemic segment 7 of 15 biopsies showed partial necrosis and 5 of 15 showed full thickness necrosis. We conclude that pulse oximetry of the intestinal wall is a valuable method of assessing intestinal viability in this model.

Animals↗
PubMed1990

Testicular sparing surgery for prepubertal teratoma of the testis: a clinical and pathological study.

We report on 5 patients 14 months to 6 1/2 years old with prepubertal teratoma of the testis treated by testicular sparing tumor enucleation. All 5 patients had no evidence of recurrence at a mean followup of 96 months. Recognizing that this is not accepted therapy for testis tumors, 17 orchiectomy specimens containing teratoma from children were histologically analyzed in cooperation with the Armed Forces Institute of Pathology Tumor Registry. All patients were prepubertal at orchiectomy (3 months to 8 years old) and all are well with a mean followup of 174 months. Histological examination revealed no foci of teratoma separate from the main tumor in any specimens. Immunohistochemical studies with placental alkaline phosphatase, a marker for malignant germ cells, were done to detect carcinoma in situ in the seminiferous tubules of these testes. This test did not reveal any intratubular malignant germ cells (carcinoma in situ). Based on our clinical experience with testicular sparing tumor enucleation, the histological findings on Armed Forces Institute of Pathology review demonstrating no associated carcinoma in situ and the universally benign behavior of prepubertal testicular teratomas, we recommend a testicular sparing operation rather than orchiectomy for testicular teratoma in prepubertal patients.

Child↗
PubMed1990

Morphometry of ampullar dark cells.

The morphologic characteristics of rat ampullar dark cells were analyzed quantitatively. Four parameters were measured: cell area per micron baseline length, membrane surface density, volume density of intercellular space, and volume density of vacuoles. No statistically significant difference was observed for any parameter, either between dark cell regions of the superior, lateral, and posterior ampullae or between different regions of dark cells within a given ampulla. The membrane surface density of the ampullar dark cells was similar to that reported for principal cells of the cortical collecting duct in the kidney. The volume density of the intercellular spaces of the dark cells was very constant, unlike that reported for epithelia involved in isotonic fluid transport. Vacuoles were found to comprise only a small portion of protoplasm in the dark cells. This new morphometry provides a basis on which to examine the response of ampullar dark cells to differing experimental conditions.

Animals↗
PubMed1989

Decreased adenosine triphosphatase activity in the absence of adrenocorticosteroids.

Changes in adenosine triphosphatase activity and cellular integrity of rat inner-ear tissues were observed after removal of adrenal steroids via bilateral adrenalectomy. Statistical significance of total and magnesium ion-dependent adenosine triphosphatase activities of the stria vascularis, spiral ligament, and ampullar dark cells from adrenalectomized animals was detected when compared with those of controls as demonstrated by fluorometric microassay. Although there was a similar reduction of activity in utricular dark-cell tissues, no significant difference between the treated and control animals was observed. An increase of intercellular space and a decrease in basolateral infoldings of cells of the stria vascularis and dark cell regions of adrenalectomized animals were observed. Such data collectively provide indirect evidence that adrenal steroids are involved in the cellular regulation of inner-ear tissues that are concerned with fluid and ionic microhomeostasis.

Adenosine Triphosphatases↗