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Biomedical subjects

C R Hamilton

Publications and source records attributed to C R Hamilton.

At least 37 records · Page 2Linked to original sources
PubMed1989

The late effects of cis-platinum on renal function.

The combination of bleomycin, etoposide and cis-platinum (BEP) is an effective treatment for germ cell tumours. To help define the role of recently developed non-nephrotoxic analogues of cis-platinum we have analysed the long term renal damage caused by this agent. We report on 22 patients studied 8-60 months following BEP chemotherapy. In the 17 cases with no pre-chemotherapy renal impairment there was a fall in mean glomerular filtration rate from 132 ml/min (95% confidence interval 123, 141) pre-chemotherapy to 103 ml/min (95% confidence interval 94, 113) on late follow up. The overall pattern is one of initial fall of glomerular filtration rate during chemotherapy, and no consistent evidence of late recovery or further deterioration; considerable individual variation is observed.

Adolescent↗
PubMed1989

The management of paratesticular rhabdomyosarcoma.

Between 1974 and 1986 15 patients presented to the Royal Marsden Hospital with paratesticular rhabdomysarcoma. Of 10 patients presenting with Stage I disease, eight were treated with adjuvant chemotherapy. Six (75%) remain continuously disease-free 1.2-8.3 years from presentation. The two who relapsed have been salvaged with further treatment and remain disease-free 7.5 years and 10.3 years from original presentation. Three patients presented with regional node involvement and two are disease-free 3.3 and 3.7 years from presentation; the other died from disease. Two patients presented with Stage III disease and one remains alive and disease-free at 7.8 years from presentation. The efficacy of chemotherapy has diminished the roles of surgery and radiotherapy following radical excision in Stage I disease. However, aggressive multi-modality approaches are relevant for metastatic disease.

Adolescent↗
PubMed1988

Complementary hemispheric specialization in monkeys.

Twenty-five split-brain monkeys were taught to discriminate two types of visual stimuli that engage lateralized cerebral processing in human subjects. Differential lateralization for the two kinds of discriminations was found; the left hemisphere was better at distinguishing between tilted lines and the right hemisphere was better at discriminating faces. These results indicate that lateralization of cognitive processing appeared in primates independently of language or handedness. In addition, cerebral lateralization in monkeys may provide an appropriate model for studying the biological basis of hemispheric specialization.

Animals↗
PubMed1987

Gastrointestinal morbidity of adjuvant radiotherapy in stage I malignant teratoma of the testis.

Between January 1963 and December 1983, 248 patients with stage I teratoma were managed by the Testicular Tumour Unit of the Royal Marsden Hospital (RMH). Before 1979, these patients were treated with adjuvant irradiation to the abdominal and pelvic lymph nodes (142 patients) to a mid-plane dose of 40 Gy in 20 fractions over 4 weeks. In 1979, a surveillance policy was adopted (106 patients) and relapsing patients treated with chemotherapy. By 2 years post-orchidectomy, seven patients (4.9%) in the irradiated group developed duodenal ulceration compared to none in the surveillance group (p = 0.05). A past medical history of duodenal ulcer was a significant risk factor for ulceration after radiotherapy (p = 0.04) whereas a past history of abdominal surgery was not (p = 0.8). It is concluded that adjuvant radiotherapy for stage I teratoma may increase the risk of peptic ulceration.

Adult↗
PubMed1987

Surveillance after orchiectomy for stage I seminoma of the testis.

Between February 1983 and July 1985, 52 patients with Clinical Stage I seminoma were observed after orchiectomy without lymph node irradiation. Seven patients (13%) have relapsed, six in retroperitoneal lymph nodes and one with abdominal node and pulmonary metastases. Relapses were diagnosed 6 to 23 months after orchiectomy, four occurring in the first year and three in the second year. Of eight patients with raised serum concentrations of HCG prior to orchiectomy none has relapsed, whereas of 14 patients with normal HCG levels one has relapsed. The significance of these observations for future management policy is discussed.

Chorionic Gonadotropin↗
PubMed1986

Radiotherapy of Kaposi's sarcoma.

Between 1958 and 1983, 91 patients with Kaposi's sarcoma were referred to the Princess Margaret Hospital. Eight patients received no specific therapy immediately following their first assessment. Twenty-seven patients were treated by local field radiotherapy, of whom 17 entered complete remission and 6 have remained relapse-free. Fifty-six patients received extended field radiotherapy, usually a single fraction of 8 Gy megavoltage gamma-ray or photon therapy; 38 achieved completed remission, and 24 have remained relapse-free for a median duration of 3 years. The actuarial relapse-free survival for patients treated by local versus extended field radiotherapy significantly favors the extended field technique although the rates of relapse after complete remission has been achieved appear similar. Immunosuppression was present in 12 patients prior to the diagnosis of Kaposi's sarcoma; these patients had a similar response rate to radiation therapy to those who were not known to be immunosuppressed. A rationale for management, and radiation technique and dose are discussed. It is concluded that radiotherapy is an effective treatment for most forms of Kaposi's sarcoma.

Adult↗
PubMed1986

Effect of biotin and(or) lysine additions to corn-soybean meal diets on the performance and nutrient balance of growing pigs.

Supplementation of a basal corn-soybean meal diet with 0 or .2% L-lysine and 0, .25 or .55 ppm biotin produced six dietary treatments in a factorial arrangement. Pig performance, post-weaning scour scores, plasma urea N (PUN) levels, N and energy balance and liver pyruvate carboxylase activity (PC) were response criteria. Crossbred pigs were fed from weaning at 4 wk of age (8.0 kg) to market weight in performance trials utilizing 552 pigs in the 35-d starter period and 384 pigs in the subsequent grower (about 21 to 50 kg) and finisher (about 50 to 95 kg) periods. Pigs remained on their respective dietary treatments for the entire experiment. Energy and N balance trials were conducted utilizing 36 barrows from the grower period (avg 44.7 kg) and 36 barrows from the finisher period (avg 90.3 kg) of the performance study. Barrows were sacrificed following completion of the 6-d collection periods to measure liver PC activity. The basal starter diet contained 17.0% crude protein (CP), 86% lysine and .22 ppm biotin. Increasing the corn:soybean meal ratio reduced the dietary levels of CP, lysine and biotin to 14.8%, .69% and .19 ppm for the basal grower diet and to 11.1%, .50% and .17 ppm, respectively, for the basal finisher diet. Lysine supplementation improved (P less than .05) average daily feed intake and average daily gain for all periods, gain:feed ratios for the starter and grower periods and reduced (P less than .01) PUN levels at the end of the starter and finisher periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1985

Simultaneous cecostomy and ileal cannulation with a modified flexible T cannula in gilts.

A surgical procedure was developed for the simultaneous cannulation of the ileum and fistulation of the cecum in breeding-age gilts to study the effects of enteric microflora on the nutritional requirements and/or status of the pig. Flexible T-shaped cannulae were made from plastic tubing, placed surgically in the caudal part of the ileum, and exteriorized in the right paralumbar fossa. After the exteriorization of the cecal apex in the right flank area, a cecal fistual was made caudoventral to the ileal cannula. Prececocolonic contents could be collected from the ileal cannulae and/or substances could be infused into the cecum. The flexible cannulae were light weight (35 g), were easily replaced when dislodged with minimal tissue trauma and minimal discomfort to the animal, and had good animal tolerance and patency in long-term experiments. The cecal fistulae allowed the direct introduction of various substances into the cecum. There was little external projection from the abdominal wall, and the fistulae were subject to minimal leakage. The procedure did not adversely affect the subsequent health or performance of the 43 gilts used in the experiment. Postmortem examination of gilts euthanatized 12 to 26 weeks postoperatively revealed normal tissue adhesions around the surgical sites with no detrimental effects on the gastrointestinal tract.

Animals↗
PubMed1984

Hemispheric differences in split-brain monkeys viewing and responding to videotape recordings.

Eight split-brain monkeys were tested for hemispheric differences in their viewing of and responses to colored videotape recordings of monkeys, people, animals, and scenery. The number of facial expressions elicited from the right hemisphere was significantly greater than the number made when using the left hemisphere. Monkeys also tended to look longer when viewing with their right hemispheres than when viewing with the left.

Animals↗
PubMed1984

Response of sows and litters to added dietary biotin in environmentally regulated facilities.

A 3-yr study was conducted to evaluate the effects of biotin on sow longevity, reproductive performance and piglet performance to weaning utilizing 161 sows and 414 litters. Sows and gilts were fed a basal corn-soybean meal diet (without any antibiotic or chemotherapeutic compounds) during gestation and lactation containing either 0 or .55 ppm added biotin. The basal diet contained .17 ppm total dietary biotin based on microbiological assay. Results indicated sow culling rates and weight gains, number of live pigs at birth, pig weights at birth and weaning, and the interval from weaning to rebreeding were similar for both treatment groups. However, sows fed the diet with added biotin weaned more (P less than .05) pigs/litter overall and at gestation-lactation period 1 than did sows fed the basal diet without added biotin, although biotin did not increase (P greater than .10) the number of pigs weaned at gestation-lactation periods 2 through 5. The incidence of dermatitis, hair loss and soundness of feet and legs did not appear to be affected by adding biotin to the diet. Thus, the addition of .55 ppm biotin to a corn-soybean meal diet fed during gestation and lactation did not improve any of the criteria measured except number of pigs weaned overall.

Animal Population Groups↗
PubMed1983

Lateralization for orientation in split-brain monkeys.

Split-brain monkeys learned with each cerebral hemisphere to discriminate lines differing in slope by 15 degrees. This type of spatial discrimination is usually performed better by the right hemisphere of humans. The left hemisphere of 8 monkeys learned this type of problem much more readily than did the right hemisphere. Learning to discriminate simple patterns in the same apparatus was done equally well by either hemisphere, demonstrating that the lateralized ability is specific to the stimuli employed.

Animals↗
PubMed1983

Discrimination of monkey faces by split-brain monkeys.

Eighteen split-brain rhesus monkeys were tested with each hemisphere for the ability to learn to discriminate photographs of the faces of other monkeys. Seven subjects also ran tests of generalization to new photographs of the discriminated monkeys; these tests confirmed that facial features pertaining to individual monkeys were learned. Equal numbers of male and female monkeys and nearly equal numbers of right and left handed monkeys were tested. Over all the monkeys there was no significant advantage in learning with either the left or right hemisphere or with the hemisphere contralateral or ipsilateral to the preferred hand. The group of 9 female monkeys, however, did shown a significant advantage in learning with the left hemisphere. Furthermore, there was a tendency for monkeys older at the time of surgery to show greater hemispheric specialization.

Animals↗
PubMed1983

The biotin status of weanling pigs fed semipurified diets as evaluated by plasma and hepatic parameters.

Twenty-four pigs were weaned at four weeks of age and fed either spray dried egg albumen (DA) or autoclaved DA (ADA) as the only protein source were used to evaluate plasma and hepatic parameters as indicators of biotin status. Pigs were fed one of four semipurified diets during the 42-day study: DA basal, DA + 1.1 g sulfamethazine/day (DA + S), ADA basal or ADA + .5 mg biotin/day (ADA + H). Autoclaving DA at 121 degrees C for 30 minutes reduced both the biotin binding properties of the avidin fraction and the trypsin inhibitor activity of DA. Pigs fed ADA and ADA + H had greater (P less than .05) liver pyruvate carboxylase (EC 6.4.1.1) activity and DNA concentrations, lower (P less than .05) plasma urea nitrogen levels and greater and more efficient (P less than .05) weight gain than either DA or DA + S fed pigs. Biotin supplementation further enhanced (P less than .05) liver DNA concentration but had no effect on the liver levels of RNA or total protein. Plasma levels of glucose and free fatty acids or blood levels of lactate and pyruvate were not influenced by the addition of biotin to the ADA basal diet.

Animals↗
PubMed1982

Hemispheric differences in split-brain monkeys learning sequential comparisons.

Twelve split-brain rhesus monkeys were tested for differences in the abilities of their two cerebral hemispheres to learn discriminations based on the comparison of sequentially-presented visual stimuli. Overall there was no generalized advantage for either the left or right hemisphere. There was, however, a significant correlation between each monkey's handedness and the hemisphere that learned more readily; the more proficient hemisphere tended to be contralateral to the preoperatively preferred hand. This result raises the possibility that handedness in monkeys may be more closely related to cognitive processing than is usually believed.

Animals↗
PubMed1979

Partial interocular transfer of brightness and movement discrimination by split-brain cats.

Interhemispheric transfer of discriminations of brightness and direction of movement, two types of stimuli which may be processed by midbrain visual areas, was compared to transfer of control patterns in cats with sections of the optic chiasm and forebrain commissures. Transfer in these split-brain cats was further compared to transfer in partially split-brain cats with sparing of either the splenium of the corpus callosum or the anterior commissure. An intact splenium was necessary for high levels of interhemispheric transfer of all of the discriminations, which implies a prominant role for cortical mechanisms in such tasks. However, animals with complete section of the corpus callosum often showed partial interocular transfer of both brightness and movement discriminations, which may reflect a limited but selective participation of subcortical areas in visual perception. Cats in which the anterior commissure was spared did not show greater transfer on any of these tasks than did cats with section of both callosum and anterior commissure.

Animals↗
PubMed1977

An assessment of hemispheric specialization in monkeys.

Split-brain monkeys learned several sets of visual discriminations with each hemisphere. Some stimuli, such as photographs of monkey's faces, were intended to favor mechanisms similar to those of man's nondominant hemisphere, while other tasks, requiring sequential comparison of visual stimuli, should favor mechanisms similar to ones in the dominant hemisphere of man. The tests uniformly demonstrated hemispheric equivalence for solving all types of problems, regardless of handedness, sex, or side of surgical retraction. A review of the literature also offers little support for the concept of hemispheric specialization in infra-human mammals although a few leads still need to be explored before abandoning the hope of finding the roots of human cerebral dominance in monkeys.

Animals↗
PubMed1975

Thyroid-stimulating hormone levels in idiopathic euthyroid goiter.

Utilizing a double antibody radioimmunoassay for human TSH we compared distribution of serum TSH in 167 normal individuals and 51 patients with idiopathic euthyroid goiter. In addition to being clinically euthyroid both groups had normal total thyroxine, and free thyroid index. Forty-two percent of the goiter group had high TSH and the general distribution of TSH values in the goiterous patients was significantly higher than normal (P less than 0.001). Anlysis of subgroups of the normal and goiter populations indicated that the high TSH could not be attributed to age, sex, use of birth control pills or differences between diffuse and multinodular goiter. TSH levels were significantly higher in patients with goiter less than 1 yr compared to goiter greater than 1 yr (P less than 0.025). In patients with goiter greater than 1 yr the TSH levels remained significantly higher than normal (P less than 0.025). These results support the hypothesis that TSH plays a role in the genesis of idiopathic goiter. The elevation may be present only early in the course of goiter development but is also present in a significant number of patients with long standing goiter.

Adult↗