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Biomedical subjects

R Robertson

Publications and source records attributed to R Robertson.

At least 91 records · Page 5Linked to original sources
PubMed1987

Renal toxicity with cumulative doses of cis-diamminedichloroplatinum-II in pediatric patients with osteosarcoma. Effect on creatinine clearance and methotrexate excretion.

Sequential corrected creatinine clearance (CCC) evaluations were obtained in 30 patients treated with intra-arterial and/or intravenous cis-diamminedichloroplatinum-II (CDP). The dose was 150 mg/M2 administered with mannitol diuresis at 2 to 3 weekly intervals. Four hundred fifty-three courses were administered (range, 6-18) over 18 months. Patients also were treated with 283 courses of high-dose methotrexate (MTX) and citrovorum factor "rescue" which were interposed between treatments. Deleterious effects of cumulative courses of CDP manifested as progressive reductions in CCC and delayed excretion of serum MTX. Severe MTX toxicity was aborted by augmenting the fluid intake and prolonging citrovorum factor rescue when elevated levels of serum MTX were detected. The first indication of renal induced CDP toxicity occurred with a cumulative dose of 450 mg/M2. At the termination of treatment (cumulative CDP dose over 1050 mg/M2) renal impairment still was present.

Child↗
PubMed1987

Identity cards for patients infected with HIV?

Dr A C Srivastava has written to us to describe a case that raises the suggestion that people infected with the human immuno-deficiency virus (HIV) should carry identity cards. We asked two physicians, a general practitioner working with patients with the acquired immune deficiency syndrome (AIDS), and a general practitioner with a special interest in medical ethics to respond to the broad issues raised by Dr Srivastava's letter.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Pathologic fracture in osteosarcoma. Impact of chemotherapy on primary tumor and survival.

Twenty patients with osteosarcoma and pathologic fractures were treated with a chemotherapeutic regimen consisting of cis-diamminedichloroplatinum-II (CDP), Adriamycin (ADR) (doxorubicin) and high-dose methotrexate with citrovorum factor "rescue" (MTX-CF). Before the introduction of the regimen, the primary tumor in two patients was treated by immediate amputation and in 13 with preoperative intra-arterial CDP. Among these 13 patients, responses (healing) were observed in 11 (one required the addition of radiation therapy). In three patients, the responses were so dramatic that, at their request, surgery was deferred and treatment exclusively with chemotherapy was instituted. Based on this experience, treatment exclusively with chemotherapy was also administered to an additional five patients who were admitted without pathologic fractures. In the course of such treatment, pathologic fractures also developed; notwithstanding, chemotherapy was maintained and healing also occurred. One of the 20 patients had pulmonary metastases at diagnosis; these were resected after treatment and pathologic examination revealed no evidence of viable tumor. The remaining 19 patients were free of pulmonary metastases but these later developed in seven patients. These data were compared to a historical control series in which 16 of 21 patients with pathologic fractures developed pulmonary metastases. Three of the chemotherapy treated patients died of nonosteosarcoma related causes (leukemia, generalized varicella, and a metabolic complication). Overall, survival was improved in the chemotherapy treated patients as compared to the historical control series: 10 of 20 versus 6 of 21, respectively. Pathologic fractures in osteosarcoma may heal under treatment with chemotherapy, which also has a favorable impact on the eradication of pulmonary metastases and survival.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Muscle activation during proprioceptive neuromuscular facilitation (PNF) stretching techniques.

Proprioceptive neuromuscular facilitation (PNF) techniques are often used to induce muscle relaxation and increase joint range of motion (ROM). However, the relationship between muscle activation and ROM with PNF is not well understood. The purpose of this study was to investigate the effect of three common PNF stretching techniques on hamstring muscle activation and knee extension. Three PNF techniques: stretch-relax (SR), contract-relax (CR) and agonist contract-relax (ACR) were applied to ten male and female subjects aged 23-36 years who were stabilized to isolate knee extension measurements. Knee joint position and EMG activity from quadriceps and hamstring muscles were computer processed throughout technique application. The results revealed mean hamstring EMG activity increased 8-43% within a given trial of ACR and CR respectively, and did not diminish across trials. SR produced a 11% decrease in mean hamstring EMG activity. ACR produced 3-6% greater knee extension values than CR and SR respectively, in spite of 71-155% greater hamstring EMG activity during ACR. The data suggest that CR and ACR do not evoke sufficient relaxation in muscles opposing knee extension to overcome tension facilitation generated by stretch. Thus, increases in ROM are achieved while the hamstrings are under considerable tension. Such tension increases muscle vulnerability to soreness and strain if stretching continues. The degree of knee extension produced via SR, although 3-6% less than CR and ACR, was achieved during simultaneous reduction in hamstring activity and may be the safer stretching technique.

Adult↗
PubMed1986

Electroencephalograms of children with permanent cortical visual impairment.

The electroencephalograms of 40 children with permanent cortical visual impairment (CVI) were studied. CVI was diagnosed in the presence of severe visual loss, normal or minimal ocular findings and clinical, electrodiagnostic and CT evidence of postgeniculate lesions involving the visual cortex. All patients had a multidisciplinary evaluation, including extensive neurological and ophthalmological investigations. The records did not contain any specific features which would be diagnostic of CVI. Isolated occipital spikes were rare and more commonly multifocal EEG disturbance was seen because of diffuse cerebral involvement. Photic stimulation was of little use in the diagnosis. Multihandicapped children with profound CVI tended to show multifocal abnormalities, no alpha rhythm and a suppressed posterior waking background in their EEGs, whereas those with more residual vision usually had an alpha rhythm. The presence or absence of alpha rhythm seemed to reflect the intactness of the striate cortex. However, the lack of alpha rhythm was not always associated with total blindness and not all children with useful residual vision had alpha rhythm.

Adolescent↗
PubMed1986

Co-activation of sprinter and distance runner muscles in isokinetic exercise.

The purpose of this study was to investigate the extent of co-activation of quadriceps and hamstring musculature in sprinters and distance runners. Nine female intercollegiate track athletes performed maximal knee extensions and flexions on a modified orthotron isokinetic dynamometer at two speeds (100 degrees and 400 degrees X s-1). Simultaneous recordings of torque, joint position, and agonist/antagonist electromyographic activity from the quadriceps and hamstrings were computer-processed. The results revealed the hamstrings to be considerably more active during knee extension than the quadriceps during flexion. The integrated electromyographic activity of co-contracting hamstrings and quadriceps, throughout the joint range, averaged 33 and 6%, respectively, of the same muscle group during its agonist phase. Hamstring co-activation increased sharply during the last 25% of knee extension, generating 58% of the integrated electromyographic agonist activity. Co-activation of the sprinters' hamstrings was four times that of distance runners (57/14%), however, the faster speed of movement (400 degrees X s-1) increased hamstring coactivation of distance runners more acutely than sprinters in the final phase of extension. The data suggest that the hamstrings are used to a much greater extent than quadriceps for limb deceleration and that the distraction of antagonist muscle tension should be considered when analyzing agonist isokinetic torques. Furthermore, the relatively high co-activation of the hamstrings, particularly during the last 25% of extension, may induce hamstring soreness or strain in vulnerable subjects.

Adult↗
PubMed1985

Transient neurologic disturbances induced by high-dose methotrexate treatment.

Temporary neurologic abnormalities were detected in 9 of 60 patients undergoing treatment with high-dose methotrexate and citrovorum factor rescue (MTX-CF) for osteosarcoma. The incidence of abnormalities and abnormalities themselves were more severe than previously reported. This was attributed to an increased dose and more frequent administration of MTX-CF. In view of the transient nature of the abnormalities, a biochemical cause is implicated, and the mechanisms by which it may occur are discussed.

Bone Neoplasms↗
PubMed1985

Control of primary osteosarcoma with chemotherapy.

High-dose methotrexate with citrovorum factor "rescue" (MTX-CF) produced an apparent complete response of the primary tumor in three patients with osteosarcoma. The response was sustained with MTX-CF, intra-arterial cis-diamminedichloroplatinum II (CDP) and Adriamycin (doxorubicin) for 18 months. Treatment was then electively discontinued. Local recurrence occurred in two patients, 6 and 4 months later, respectively. MTX-CF was reinstated and a complete response was again achieved in one patient. This has been maintained for 15+ months with MTX-CF and intra-arterial CDP administered for 13 of the 15+ months. Reinduction with MTX-CF failed in the second relapsed patient but an apparent remission was again achieved with radiation and intra-arterial CDP. This has been maintained with intravenous CDP, cyclophosphamide and phenylalanine mustard for 14+ months. A complete response in the primary tumor was still present in the nonrelapsed patient, 42 months from diagnosis. All patients have remained free of pulmonary metastases, 40+ to 42+ months from diagnosis.

Adolescent↗
PubMed1985

Successful treatment of pulmonary and abdominal metastatic osteosarcoma.

A patient with telangiectatic osteosarcoma of the proximal fibula while receiving adjuvant chemotherapy, developed pulmonary and, later, mesenteric metastases. The pulmonary metastases were resected and the mesenteric metastasis was eradicated with surgery and intra-arterial cis-diamminedichloroplatinum II. This represents an additional example of an alteration in the clinical pattern of metastases induced by chemotherapy and the ability to achieve cure with a multidisciplinary approach.

Adolescent↗
PubMed1985

Comparison of intra-arterial cis-diamminedichloroplatinum II with high-dose methotrexate and citrovorum factor rescue in the treatment of primary osteosarcoma.

A randomized two-arm study was undertaken to determine relative tumoricidal effects of intra-arterial cis-diamminedichloroplatinum II (I/A-CDP) and high-dose methotrexate with citrovorum factor rescue (MTX-CF) in the treatment of the primary tumor in patients with osteosarcoma. Responses were evaluated by clinical, radiographic, angiographic, and pathologic parameters. Fifteen patients were randomized to receive MTX-CF and 15 to I/A-CDP. In the MTX-CF arm there were four responses (three complete responses, one partial response) whereas in the I/A CDP arm there were nine responses (seven complete responses, two partial responses). Two patients who failed MTX-CF and requested alternative treatment with I/A-CDP also responded. The total I/A-CDP response was 11/17.

Adolescent↗
PubMed1984

Five-year surveillance of aminoglycoside usage in a university hospital.

Because an increased incidence of nosocomial bacteremia due to gentamicin-resistant organisms occurred in our hospital, amikacin was substituted for gentamicin as the primary empiric aminoglycoside. Prospective surveillance of aminoglycoside use and of bacterial resistance to aminoglycosides was done before and after the substitution. We compared the baseline period when gentamicin was the primary aminoglycoside with the subsequent period when amikacin accounted for 81% of aminoglycoside used. During the two periods the patient population did not differ with regard to indications for aminoglycoside therapy. Among the gram-negative organisms isolated, rates of amikacin resistance during the baseline (1.1%) and usage (1.05%) periods were not significantly different (p greater than 0.6). Resistance to gentamicin and tobramycin during the period of amikacin use showed a statistically significant decrease (p greater than 0.001) due to decreased resistance to gentamicin of Providencia, Serratia, indole-positive Proteus, and decreased resistance to tobramycin of Pseudomonas aeruginosa. Unrestricted use of amikacin does not necessarily lead to increase in amikacin resistance but may lead to a decrease in resistance to gentamicin and tobramycin among gram-negative organisms.

Amikacin↗
PubMed1983

Changes in the visual evoked potential to pattern reversal with lithium medication.

Previous reports in the literature have suggested that lithium medication does not affect the VEP to flash stimulation. It was predicted that this would not be true for pattern reversal stimulation. Seven patients had their pattern evoked potential measured using a 42' check to fractional pattern displacement of 1/4, 1/2, 3/4 and full square. The VEP was measured before, 1 week after and 5 weeks after the commencement of lithium medication. The results show that there is a significant increase in both the N65-P95 and P95-N125 amplitudes when the 'before lithium' sessions are compared to 'after lithium.' Seven normal subjects matched for the age and sex of the patient group were tested twice, once as a 'control' and a further 5 weeks after this. No significant differences were found in the 'control' sessions between patient and normal groups although a significant difference in both the N65-P95 and P95-N125 amplitude after the treatment of the patient group with lithium was found.

Adult↗
PubMed1983

Y chromosome length related to fetal loss.

The Y/20 ratio (length of Y chromosome/length of chromosome 20) was examined among 216 males, 108 of whose wives had a history of repeated abortions (study group), and 108 who were mentally retarded (controls). There was no significant difference in frequency of long Y (Y/20 equal to or greater than 1) between the study group and controls. Also, there was the expected male: female ratio among normal living children of couples in the study group, and the Y/20 ratio was not significantly increased among fathers with abnormal male offspring. However, wives of long Y males were more likely to have at least one abnormal male birth, compared with other wives (this approached statistical significance, p less than 0.08). In addition, a significantly higher frequency of long Y was found in a subset of affected males whose wives had 2 or more spontaneous abortions plus some other abnormal pregnancy outcome. Although the findings reported here do not strongly support a causal relationship, they at least suggest an association between long Y chromosome and abnormal fetal development.

Abortion, Habitual↗