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Biomedical subjects

D Archer

Publications and source records attributed to D Archer.

At least 37 records · Page 2Linked to original sources
PubMed1997

Chemotherapy for symptom control in recurrent squamous cell carcinoma of the head and neck.

BACKGROUND: The role of chemotherapy in patients with recurrent squamous cell carcinomas of the head and neck (SCCHN) is unclear. The aim of this study was to assess the ability of combination chemotherapy to control symptoms in this setting. PATIENTS AND METHODS: Using a prospectively accrued database all patients referred for chemotherapy with symptomatic relapse following surgery were identified. Objective response was recorded using standard criteria and maximum symptom response was assessed retrospectively from case notes using a published scoring scale. RESULTS: A total of 57 (median age 56, range 37-85) patients were studied who had received mainly cisplatin/5-fluorouracil combinations. Thirty-seven had previously received radiotherapy. Fifty-two patients had evaluable disease; 18 (35%) had objective responses (14 PRs and 4 CRs). There were a total of 103 symptoms recorded with eight different individual symptoms. Forty-four (43%) symptoms improved on treatment, 52 (50%) were unchanged and 7 (7%) worsened. The number of patients with improvement in the most frequently recorded symptoms were as follows: pain 11/28 (39%), swelling 12/23 (52%) and dysphagia 6/18 (33%). Sixty-seven percent of patients with objective response also had an improvement in their symptoms but a significant proportion (33%) of non-responders had a symptomatic response. Lack of objective response was not correlated with worsening symptoms. Grade 3/4 toxicity was uncommon (6%-17%) and there were no toxic deaths. A majority of patients (82%) experienced either no change or an improvement in performance status. CONCLUSION: These results demonstrate that chemotherapy improves many of the symptoms associated with recurrent SCCHN, without deterioration in performance status. Symptomatic improvement is more likely if there is evidence of significant tumour shrinkage, but even non-responding patients can benefit.

Adult↗
PubMed1997

The effect of skull-pin insertion on cerebrospinal fluid pressure and cerebral perfusion pressure: influence of sufentanil and fentanyl.

This randomized prospective study measured the effects of an intravenous opioid bolus on cerebrospinal fluid pressure (CSFP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) during skull-pin insertion. Twenty-two adult patients scheduled for elective craniotomy for supratentorial lesions were studied. Outcome variables were MAP, heart rate (HR), and lumbar CSFP. The standardized anesthetic regimen included fentanyl (2 microg/kg), thiopental (5-7 mg/kg), lidocaine (1.5 mg/kg), isoflurane (0.3-0.7 minimum alveolar anesthetic concentration), and vecuronium (0.1 mg/kg). During stable anesthesia, sufentanil (0.8 microg/kg) or fentanyl (4.5 microg/kg) was given as a bolus before skull-pin insertion. The hemodynamic effects of the opioid injection were modified with phenylephrine and/or atropine when indicated. CSFP remained unchanged in both treatment groups. MAP and CPP increased approximately 10 mm Hg after skull-pin insertion (P<0.001). In the sufentanil group, HR decreased approximately 10 bpm after opioid injection and remained decreased throughout the study. In fentanyl-treated patients, HR decreased 8 bpm after opioid injection but returned to preopioid rates after skull-pin insertion. In conclusion, in anesthetized patients, an intravenous bolus of fentanyl or sufentanil prior to skull-pin insertion results in stable values of CSFP, CPP, BP, and HR when the hemodynamic effects of the opioid are modified with phenylephrine and atropine.

Adjuvants, Anesthesia↗
PubMed1996

Comparison of skin-to-skin contact with standard contact in low-birth-weight infants who are breast-fed.

OBJECTIVE: To evaluate the effects of maternal-infant skin-to-skin contact (SSC) vs standard contact (SC) on low-birth-weight infants' physiological profile, maternal milk production, and duration of breast-feeding. DESIGN: Prospective, randomized, interventional study with cohort followed up for 6 months after discharge from the hospital. SETTING: Special care nursery with follow-up telephone calls after discharge from the hospital. PATIENTS: Fifty infants, with birth weights less than 1500 g and whose mothers planned to breast-feed, randomized to 2 groups: SSC (experimental) and SC (control). INTERVENTION: In the SSC group, infants were clothed in diaper and held upright between mothers' breasts; both mother and infant were covered with a blanket. In the SC group, infants were clothed, wrapped in blankets, and held cradled in mother's arms. MAIN OUTCOME MEASURES: Infant physiological data, ie, oxygen saturation, heart rate, respiratory rate, and axillary temperature; maternal milk production; and duration of breast-feeding. RESULTS: Oxygen saturation was higher during SSC than during SC (P < .001); 11% of the oxygen saturation recordings during SSC vs 24% during SC indicated the values less than 90% (P < .001). A more stable milk production was noted in the SSC group. No differences were noted in infant temperature, heart rate, or respiratory rate. Ninety percent of mothers in the SSC group vs 61% in the SC group continued breast-feeding for the duration of the infants' hospitalization (P < .05), and 50% in the SSC group vs 11% in the SC continued breast-feeding through 1 month after discharge (P < .01). CONCLUSIONS: During SSC with their mothers, low-birth-weight infants maintain a higher oxygen saturation and are less likely to have desaturation to less than 90% oxygen than are infants exposed to SC. Mothers in the SSC group are more likely to continue breast-feeding until 1 month after discharge.

Adult↗
PubMed1996

[Peroperative risks in cerebral aneurysm surgery].

The perioperative complications associated with cerebral aneurysm surgery require a specific anaesthetic management. Four major perioperative accidents are discussed in this review. The anaesthetic and surgical management in case of rebleeding subsequent to the re-rupture of the aneurysm is mainly prophylactic. It includes haemodynamic stability assurance, maintenance of mean arterial pressure (MAP) between 80-90 mmHg during stimulation of the patient such as endotracheal intubation, application of the skull-pin head-holder, incision, and craniotomy. The aneurysmal transmural pressure should be adequately maintained by avoiding an aggressive decrease of intracranial pressure. Once the skull is open, the brain must be kept slack in order to decrease pressure under the retractors and avoid the risks of stretching and tearing of the adjacent vessels. If, despite these precautions, the aneurysm ruptures again. MAP should be decreased to 60 mmHg and the brain rendered more slack, in order to allow direct clipping of the aneurysm, or temporary clipping of the adjacent vessels. The optimal agents in this situation are isoflurane (which decreases CMRO2), intravenous anaesthetic agents (inspite their negative inotropic effect, they may potentially protect the brain) and sodium nitroprusside. Vasospasm occurs usually between the 3rd and the 7th day after subarachnoid haemorrhage. It may be seen peroperatively. The optimal treatment, as well as prophylaxis, is moderate controlled hypertension (MAP > 100 mmHg), associated with hypervolaemia and haemodilution, the so-called triple H therapy, with strict control of the filling pressures. Other beneficial therapies are calcium antagonists (nimodipine and nicardipine), the removal of the blood accumulated around the brain and in the cisternae, and possibly local administration of papaverine. Abrupt MAP increases are controlled in order to maintain adequate aneurysmal transmural pressure. Beta-blockers, local anaesthetics administered locally or intravenously, a carefully titrated level of anaesthesia, a maintained volaemia play a protective role. Cerebral oedema is sometimes already present at the opening of the skull or may arise later, due to a high pressure under the retractors, to the surgical manipulations of the brain or to brain ischaemia subsequent to temporary clipping. Its treatment is aggressive, with intravenous agents, mannitol, deep hypocapnia and/or lumbar drainage. Prophylaxis, according to the "brain homeostasis concept", is the preferred method to avoid these four peroperative accidents. It includes normal blood volume, normoglycaemia, moderate hypocapnia, normotension, soft manipulation of the brain and optimal brain relaxation.

Anesthesia, General↗
PubMed1996

The effects of bolus administration of opioids on cerebrospinal fluid pressure in patients with supratentorial lesions.

In many studies reporting an increase in cerebrospinal fluid pressure (CSFP) after opioid administration, concomitant decreases in mean arterial pressure (MAP) have been observed. Autoregulatory cerebral vasodilation may therefore have been a factor in the CSFP increases. We tested the hypothesis that increases in CSFP after bolus injection of opioids could be minimized by modifying concomitant decreases in MAP with phenylephrine. Thirty-three patients with supratentorial mass lesions were studied in a randomized, prospective, double-blind, saline-controlled comparative trial. The principal outcome measures were lumbar CSFP, MAP, and heart rate (HR). Study drugs, sufentanil 0.8 micrograms/kg (n = 12), fentanyl 4.5 micrograms/kg (n = 11), or normal saline (n = 10), were injected intravenously (IV) during stable general anesthesia with 0.3-0.7 minimum alveolar anesthetic concentration (MAC) of isoflurane in oxygen and controlled ventilation (end-tidal carbon dioxide 32-35 mm Hg). Phenylephrine 50-100 micrograms was injected IV when MAP decreased by more than 15% of initial values, and atropine 0.5 mg IV when HR decreased to less than 45 bpm. Opioid administration was associated with significant decreases in MAP, 21 +/- 9 mm Hg (mean +/- SD) in the sufentanil group and 16 +/- 7 mm Hg in the fentanyl group; P < 0.001. These decreases in MAP were of short duration (i.e., corrected with 1-2 min). Patients in the sufentanil group needed more phenylephrine than patients in the fentanyl group (170 +/- 89 micrograms vs 100 +/- 47 micrograms; P < 0.05). No significant change in the CSFP was seen in either the sufentanil (1 +/- 6 mm Hg) or fentanyl-treated patients (O +/- 2 mm Hg). No significant changes in MAP or CSFP were observed in the saline-treated patients. HR decreased after injection of either study drug (P < 0.01) but remained unchanged in the saline group. In summary, during stable anesthesia with isoflurane in oxygen, bolus injections of fentanyl or sufentanil, despite producing rapidly corrected mean decreases in MAP of 18% and 25%, respectively, were not associated with any change in CSFP.

Adult↗
PubMed1996

The Community Health Advocacy Program: changing the relations between communities and the medical campus.

Both CHAP and service-learning are unique new additions to medical education. The Medical School, Swearer Center for Public Service, and the Providence community have shown tremendous support and commitment. This commitment continues with the medical school's hiring of the Service-Learning Coordinator, who will help direct CHAP and organize service learning opportunities for medical students. CHAP provided me with an incredible learning experience, both frustrating and empowering. I was able to make sense out of medicine in the context of community health and also help others make sense of why an understanding of the communities in which they work and live was important to their medical education. On the whole I am pleased with the work and progress of CHAP as well as the service learning. I look forward to its future success and the newly forged partnerships of participating communities and the Brown Medical School campus.

Community Health Services↗
PubMed1995

Lack of magainin-like activity in human cervical tissue.

PROBLEM: The cervix plays an integral role in innate immunity of the human reproductive tract. Magainins are antimicrobial and spermicidal peptides recently described in human submandibular glands. We investigated the human cervix for magainin-like peptides. METHOD: Histologic sections of frozen and paraffin embedded cervical tissue from nine subjects were separately incubated with two rabbit, polyclonal, anti-magainin antibodies (CB-2 and CB-7) to investigate for magainin-like activity in the human cervix. RESULTS: There was no specific staining of cervical columnar cells within the endocervical canal or in the endocervical crypts. Magainin-like immunoreactivity in the human submandibular gland confirmed previous observations. CONCLUSION: Antigen related to magainin-like peptides were not discovered in the human cervix.

Animals↗
PubMed1995

Molecular characterization of endothelin receptors and the effect of insulin on their expression in retinal microvascular pericytes.

Microvascular pericytes contain predominantly endothelin A (ET(A))-like binding sites and also a smaller number of ETB binding sites. In this study we verified the expression of both receptors in these cells. We then examined the effect of insulin, a potent mediator of vasodilatation, on the expression of these receptors in pericytes by Northern hybridization. Northern hybridization studies showed that ET(A) mRNA levels were not influenced by exposure to insulin (1 x 10(-7) M). By contrast, ETB receptor mRNA, which was minimal under basal conditions, was significantly increased by 4 h after exposure to insulin.

Animals↗
PubMed1994

Quantitative analysis of hyaluronan in vitreous humor using capillary electrophoresis.

Capillary electrophoresis was used for the separation and quantitative analysis of the glycosaminoglycan hyaluronan in human and bovine vitreous with detection by UV absorbance at 200 nm. Calibration was carried out using standards made up from known concentrations of hyaluronan of umbilical cord origin. The purity of the standard was examined by 1H NMR (nuclear magnetic resonance). Concentrations as low as 25 micrograms/mL could be detected by capillary electrophoresis. Confirmation that the signal was due to hyaluronan was obtained by depolymerization of the native mucopolysaccharide by hyaluronidase. This resulted in loss of the hyaluronan peak and appearance of several new peaks corresponding to the oligomeric fragments which had shorter migration times. Capillary electrophoresis is a reproducible and sensitive technique for the quantification and characterisation of hyaluronan in vitreous samples.

Animals↗
PubMed1993

Head and neck sarcomas: prognostic factors and implications for treatment.

One hundred and thirty patients with soft tissue sarcoma of the head and neck were treated at the Royal Marsden Hospital between 1944 and 1988. Pathological review was possible in 103 of these cases; only pathologically reviewed cases have been analysed. The median age at presentation was 36 years, and 53% were male. Four had neurofibromatosis type I, and one previous bilateral retinoblastoma. Six had undergone previous radiotherapy, 12 to 45 years prior to developing sarcoma. The tumours were < or = 5 cm in 78% of cases and high grade in 48%. Only one patient presented with lymph node metastases and only one with distant metastases (to lung). Malignant fibrous histiocytoma was the commonest histological type, occurring in 30 cases. The overall 5 year survival was 50% (95% CI 39-60). Local tumour was the cause of death in 63% of cases and 5 year local control was only 47% (95% CI 36-58) with local recurrence occurring as late as 15 years after treatment. The only favourable independent prognostic factor for survival was the ability to perform surgery (other than biopsy), with or without radiotherapy, as opposed to radiotherapy alone (hazard ratio 0.39; P = 0.003). Only one patient had a biopsy with no further treatment. Favourable independent prognostic factors for local control at 5 years were site (tumours of the head as opposed to the neck, hazard ratio 0.42; P = 0.02) and modality of treatment (combined surgery and radiotherapy compared to either alone, hazard ratio 0.31; P = 0.002). Patients in the combined modality and single treatment modality groups were well balanced for T stage, grade and tumour site. The patients in the combined treatment group had less extensive surgery, yet their local recurrence-free survival was longer. Unlike soft tissue sarcomas at other sites, those in the head and neck region more often cause death by local recurrence. The addition of radiotherapy to surgery may result in longer local recurrence-free survival.

Adult↗
PubMed1993

Potentially misleading bone scan findings in patients with hepatoblastoma.

Eleven patients who underwent nuclear medicine bone scanning were reviewed to determine the incidence of bone scan abnormalities associated with hepatoblastoma. Of these, six patients had abnormal bone scan findings--four with focal involvement. Correlating plain radiographs and/or follow-up nuclear bone scans were available for three of these four. All plain films indicated the presence of osteoporosis. Follow-up scans showed improvement or resolution of abnormalities. None of the patients had documented metastatic bone disease. While there has been no prior reported association, the authors attribute the abnormal bone scan findings to a paraneoplastic syndrome of osteoporosis associated with this primary tumor. They conclude that bone scanning is not routinely indicated in the initial diagnostic staging of hepatoblastoma.

Bone Neoplasms↗
PubMed1992

Loss of cerebral regulation during cardiac output variations in focal cerebral ischemia.

Focal cerebral ischemia was induced in anesthetized macaque monkeys by unilateral middle cerebral artery occlusion. The effect of blood volume expansion by a colloid agent and subsequent exsanguination to baseline cardiac output (CO) on local cerebral blood flow (CBF) was measured by the hydrogen clearance technique in both ischemic and nonischemic brain regions. Cardiac output was increased to maximum levels (159% +/- 92%, mean +/- standard error of the mean) by blood volume expansion with the colloid agent hetastarch, and was then reduced a similar amount (166% +/- 82%) by exsanguination during the ischemic period. Local CBF in ischemic brain regions varied directly with CO, with a correlation coefficient of 0.89 (% change CBF/% change CO), while CBF in nonischemic brain was not affected by upward or downward manipulations of CO. The difference in these responses between ischemic and nonischemic brain was highly significant (p less than 0.001). The results of this study show a profound loss of regulatory control in ischemic brain in response to alterations in CO, thereby suggesting that blood volume variations may cause significant changes in the intensity of ischemia. It is proposed that CO monitoring and manipulation may be vital for optimum care of patients with acute cerebral ischemia.

Animals↗