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Biomedical subjects

J Hibbert

Publications and source records attributed to J Hibbert.

At least 19 recordsLinked to original sources
PubMed1995

Except for alanine, muscle protein catabolism is not influenced by alterations in glucose metabolism during sepsis.

OBJECTIVE: To assess any relationship between hyperglycemia and muscle protein catabolism associated with critical illness. DESIGN: Cohort analytic study. SETTING: Clinical research center and intensive care unit of a university hospital. PARTICIPANTS: Six healthy volunteers and five patients with severe sepsis. INTERVENTIONS: Study subjects were given infusions of 6,6,d2 glucose and 15N lysine for 6 hours. After infusion of the stable isotopes for 2 hours (basal period), dichloroacetate, which accelerates pyruvate oxidation, was given (dichloroacetate period). Leg blood flow was measured by indocyanine green dye dilution, and femoral artery and vein substrate concentrations were quantitated. MAIN OUTCOME MEASURES: The metabolic rates of glucose production, oxidation, and clearance; the whole-body protein breakdown rate; and the net efflux of amino acids from the leg were determined. RESULTS: In comparison with the healthy volunteers, septic patients had significant elevations in glucose production, oxidation, and clearance, accelerated protein catabolism, and greater net peripheral efflux of amino acids. Dichloroacetate significantly decreased glucose production and increased the percentage of glucose directed toward oxidation in both healthy volunteers and septic patients. However, this dichloroacetate-induced perturbation of glucose utilization had no significant effect on whole-body protein breakdown or the efflux of specific amino acids from the leg except for alanine, whose net efflux doubled (P < or = .05). CONCLUSIONS: The findings of this study demonstrate a universal acceleration in the metabolic rates of both intermediary glucose metabolism and protein/amino acid catabolism during sepsis. Except for alanine, however, there appears to be no coupling between these two physiologic responses to sepsis.

Adult↗
PubMed1995

The use of the Wallstent endovascular prosthesis in the treatment of malignant inferior vena cava obstruction.

We report three cases of inferior vena cava (IVC) obstruction due to metastatic liver disease treated with a self-expanding Wallstent endoprosthesis (Schneider SA, Zurich, Switzerland). All three patients experienced symptomatic relief during their remaining few weeks of life. The Wallstent is effective and easy to deploy, and should be considered for use in the management of such patients. The literature to date on IVC stenting is also reviewed.

Aged↗
PubMed1994

The prognostic value of individual histologic grading parameters in small lingual squamous cell carcinomas. The importance of the pattern of invasion.

BACKGROUND: The histologic grading of the deep invasive margin of oral squamous cell carcinoma recently has been shown to have prognostic value, but previous series have not been homogeneous enough to allow grading parameters to be assessed individually. METHODS: Forty-seven small lingual carcinomas limited to the lateral border of the tongue and treated by radiotherapy were graded histologically at their deep invasive front. Clinical and grading parameters were correlated by statistical tests performed by permutational techniques. RESULTS: Carcinoma recurred locally in 6 patients, and metastases developed in 19. Local recurrence correlated with Broders' grade (P = 0.0143), keratinization (P = 0.017) and pattern of invasion (P = 0.0195). Metastasis had a highly significant correlation with Broders' grade (P < 0.001), pattern of invasion (P < 0.001), and invasive front grading total score (P < 0.001). Seven of 8 carcinomas with diffuse infiltrating patterns metastasised, whereas only 4 of 25 with large islands or a broad infiltrating pattern metastasized. CONCLUSIONS: The usefulness of the deep invasive front grading system for small lingual carcinoma was demonstrated. The pattern of invasion was the component of the grading system that had the closest correlation with metastasis and recurrence in this type of carcinoma.

Carcinoma, Squamous Cell↗
PubMed1994

Can preoperative and postoperative CEA predict survival after colon cancer resection?

Although elevated preoperative carcinoembryonic antigen (CEA) levels are associated with a poor prognosis, little has been written regarding the correlation of CEA response following curative resection of colorectal cancer and its relationship to survival. The purpose of this study, therefore, was to retrospectively evaluate survival in three groups of patients undergoing curative resection (Dukes B and C) for colorectal carcinoma: 1) elevated preoperative CEA/elevated postoperative CEA (EL/EL); 2) elevated preoperative CEA/normal postoperative CEA (EL/NL); and 3) normal preoperative CEA/normal postoperative CEA (NL/NL). A normal CEA was defined as a value < 5.0 ng/mL. Levels were drawn the day before surgery and between 2 and 4 weeks postoperatively. Patients were evaluated for age, sex, histologic grade, CEA levels (pre and postoperative), nerve and venous invasion, tumor site, and survival. There were no significant differences with respect to age, sex, Dukes stage, tumor site, histologic grade, or incidence of nerve or vascular invasion among the three groups. Five-year survival was significantly worse for patients with elevated preoperative CEA levels compared to those with normal preoperative CEA (53% versus 64%, P < 0.05), and for the EL/EL group compared with either of the other two groups (EL/EL: 66.6 +/- 11.8; EL/NL: 87.7 +/- 10.2; Group 3: 93.4 +/- 9.5, P < 0.05 ANOVA). The results indicate that a preoperative elevated CEA, particularly one that fails to decrease to normal postoperatively following a curative resection for colorectal carcinoma, represents a poor prognostic factor. Use of the CEA response may be useful for identifying a subgroup of colorectal cancer patients who are candidates for adjuvant chemotherapy.

Adenocarcinoma↗
PubMed1992

Comparison of indirect calorimetry and a new breath 13C/12C ratio method during strenuous exercise.

A new stable isotope method for the determination of substrate oxidation rates in vivo is described and compared with indirect calorimetry at rest and during high-intensity exercise (30 min at 80-85% maximal O2 uptake capacity) in six well-trained cyclists. This method uses the absolute ratios of 13C/12C in expired air, endogenous glucose, fat, and protein in addition to O2 consumption and is independent of CO2 production (VCO2). Carbohydrate and fat oxidation rates at rest, calculated by both methods, were not significantly different. During exercise the breath 13C/12C ratio increased and reached a steady state after 15-20 min. Carbohydrate oxidation rates during exercise were 39.4 +/- 5.2 and 41.7 +/- 5.7 mg.kg-1.min-1 [not significant (NS)], and fat oxidation rates were 7.3 +/- 1.3 and 6.9 +/- 1.2 mg.kg-1.min-1 (NS), using indirect calorimetry, and the breath ratio method, respectively. We conclude that the breath 13C/12C ratio method can be used to calculate substrate oxidation under different conditions, such as the basal state and exercise. In addition, the results obtained by this new method support the validity of the underlying assumption that indirect calorimetry regards VCO2 as a reflection of tissue CO2 production, during exercise in trained subjects, even up to 80-85% maximal O2 uptake.

Adult↗
PubMed1990

The effect of the level of dietary protein, carbohydrate and fat on urea kinetics in young children during rapid catch-up weight gain.

The kinetics of urea metabolism were measured in children recovering from severe malnutrition. For a period of up to 10 d they received one of four diets which provided 711 kJ (170 kcal)/kg per d. Two groups received a diet with a high protein:energy (P:E) ratio of 10-6% (HP), enriched with either fat (HP/F) or maize starch and sucrose (HP/C). Two groups received a diet with a low P:E ratio of 8.8% (LP), enriched with either fat (LP/F) or maize starch and sucrose (LP/C). The rate of weight gain on the HP diets was significantly greater than on the LP diets. There was no difference in urea production between any of the four diets: HP/F 1.23 (SE 0.12), HP/C 1.37 (SE 0.14), LP/F 1.64 (SE 0.22), LP/C 1.15 (SE 0.15) mmol nitrogen/kg per h. On the HP diets urea excretion was 0.77 (SE 0.07) mmol N/kg per h, 61% of production. There was significantly less urea excreted in the urine on diet LP/C than on LP/F (0.36 (SE 0.05) and 0.64 (SE 0.04) mmol N/kg per h respectively). A significantly greater percentage of the urea production was hydrolysed on the LP diets (61%) compared with the HP diets (39%), with the consequence that 50% of urea-N produced was available for synthetic activity on the LP diets compared with 30% on the HP diets. The increase in the urea hydrolysed on the LP diets was equivalent in magnitude to the decreased intake of N, so that overall intake plus hydrolysis did not differ between the LP and the HP diets. Crude N balance was similar on diets HP/F, HP/C and LP/C, but was significantly reduced on diet LP/F. These results show that there is an accommodation in urea kinetics during rapid catch-up weight gain, which becomes evident when the P:E ratio of the diet falls to 8.8%. It is proposed that, for a P:E ratio of 8.8%, protein is limiting for catch-up growth. When the intake has a P:E ratio of 8.8% the pattern of urea kinetics can be modified by the relative proportions of fat and carbohydrate in the diet. The measurement of urea kinetics provides a useful approach to the definition of the adequacy of the protein in the diet.

Child, Preschool↗
PubMed1990

The reliability of palpation in the assessment of tumours.

There is now a joint UICC-AJC classification for cervical lymph nodes based mainly on the size of the nodes. There is a recognized error in palpation, not only for detecting the presence of tumour but also its size. This study used an animal tumour model system to compare the ability of 6 independent observers of varying experience to detect and stage superficially transplanted growths. A preclinical medical student was as good as a Consultant ENT Surgeon in predicting the presence of tumour but the ability to stage tumours accurately was related to experience. Whilst the most experienced observers accurately estimated the size of tumours less than 2 cm, they were less accurate for larger (greater than 2 cm) tumours which were constantly understaged. This phenomenon may have important clinical implications particularly related to current nodal staging criteria.

Animals↗
PubMed1990

Identification of hypoxaemia in children having tonsillectomy and adenoidectomy.

A series of children having tonsillectomy and adenoidectomy was investigated for hypoxaemia during sleep and to assess the value of signs and symptoms as predictors of hypoxaemia. Forty-four children were studied the night before surgery. Oxygen saturation (SaO2) was measured whilst the child was awake using a pulse oximeter and when the child was asleep oxygen saturation. ECG and chest impedance were continuously monitored and recorded. In addition, 20 control children having urological surgery were studied in the same way. All the measures of hypoxaemia (awake SaO2, baseline asleep SaO2, number of hypoxaemic episodes) differed significantly between patients and controls (P less than 0.01). When significant hypoxaemia was defined as a baseline sleeping SaO2 below 90% or one dip in SaO2 of at least 10% below the baseline per hour 15 children were found to have abnormal studies. These children could not be identified from history or clinical examination but using the criteria of mouth breathing, audible respiration at rest and an awake SaO2 of less than 96%, 14 of the 15 children were accurately identified (93% sensitivity, 86% specificity). Thus a combination of the physical signs of mouth breathing and measurement of oxygen saturation whilst awake may provide a useful clinic screening test for children suspected of suffering from sleep apnoea.

Adenoidectomy↗
PubMed1990

Technetium-99m (v) dimercaptosuccinic acid: a clinical and scintigraphic study in an animal tumour model.

Technetium-99m (99mTc) (v) dimercaptosuccinic acid (DMSA) is a new tumour-imaging agent which has been used to image head and neck squamous carcinoma. This study used an established rabbit tumour model to compare palpation versus planar scintigraphy in the detection of superficially transplanted cancers. Palpation detected 83% of tumours measuring less than 2 cm compared with 58% for scintigraphy. Overall, the sensitivity for palpation was 88% (77% specificity) compared with 50% (63% specificity) for scintigraphy.

Animals↗
PubMed1989

Rhabdomyosarcoma of the alveolar ridge in an adult.

Rhabdomyosarcoma of the head and neck is rare in adults, and past reports indicate that it is a more aggressive disease than that which is found in children. We report the case of a 63-year-old woman with an alveolar type of rhabdomyosarcoma located on the mandibular alveolar ridge. Rhabdomyosarcoma of the oral cavity appears to carry a particularly poor prognosis, especially when bone is involved. Multimodal treatment with surgery, radiation therapy, and chemotherapy is indicated in all patients.

Alveolar Process↗
PubMed1986

Assessment of facial reinnervation by use of chronic electromyographic monitoring.

The study of muscle reinnervation has been difficult because of lack of an accurate, reproducible method to monitor return of function. Visual assessment relies on subjective interpretation. Histology provides anatomic, not functional, information. Electromyography and anatomic tracing have been most effective in evaluating physiologic return of muscle function. It has been difficult to assess the timing of functional return electromyographically because measurements are intermittent and electrode placement varies. A method was designed to allow long-term monitoring of electromyographic (EMG) activity in the facial musculature of the rabbit. Sixteen rabbits were monitored for at least 1 month or until return of normal EMG activity was identified. Various levels of injury (nerve crush, transection without repair, and transection with immediate end-to-end anastomosis) were evaluated. EMG evidence of reinnervation was seen in all animals with nerve crush injuries as well as those with anastomoses. Physiologic continuity of the nerves was then evaluated by retrograde transport of horseradish peroxidase. All muscles showing return of EMG activity had uptake of HRP into the appropriate brain stem motor neurons. The denervated muscles showed no HRP uptake. The information gained in this study shows potential for use of this technique in comparing functional return of muscle activity between different reinnervation methods.

Animals↗
PubMed1986

Studies of progressive glomerular sclerosis in the rat.

To obtain a better understanding of the sequential development of sclerosis in immune glomerular disease, the authors induced experimental membranous nephropathy in unilaterally nephrectomized rats and evaluated the lesions that developed over a 35-week period. Serial renal biopsies were examined by light and immunofluorescence microscopy for IgG, C3, neoantigens of the membrane attack complex (MAC), and interstitial (Type III) and basement membrane (Type IV) collagen. Urinary protein excretion increased from 208 +/- 19 mg/day to 308 +/- 36 mg/day during the period of observation. Progressive mesangial sclerosis, crescent formation, and interstitial fibrosis developed in association with deposition of Type IV but not Type III collagen in the glomeruli. Capillary wall deposits of IgG, C3, and MAC gradually decreased, whereas coarse granular deposits of C3 and MAC were visible in sclerotic areas beginning at 8 weeks. The appearance of complement components in early sclerotic lesions raises the possibility that they are of pathogenetic importance. The absence of interstitial collagen in sclerotic glomeruli suggests that the components of the lesion are produced solely by glomerular cells.

Animals↗
PubMed1985

Interstitial irradiation for squamous carcinoma of the oral cavity.

Interstitial radiation delivered by iridium 192 implants was used to treat 38 patients with squamous carcinoma of the oral cavity. Thirty-six patients had either T1 or T2 tumours and no patient had palpable nodes at the time of implantation. Control of the primary tumour was achieved in all but 2 patients; these 2 were successfully treated by surgery. Fifteen patients (39%) went on to develop metastatic neck nodes. Nine were cured by radical neck dissection but the remaining 6 died of their disease. This gives a 5-year actuarial survival of 81%. Since all deaths occurred after the development of metastatic disease in the neck with control of the primary lesion, the evidence for and against prophylactic treatment of the neck lymphatics in clinically negative necks was reviewed. Prophylactic irradiation of the neck is probably preferable to any form of neck dissection but clear evidence that this improves long-term survival compared with careful follow-up and radical neck dissection for palpable nodes is still lacking.

Adult↗
PubMed1983

The effects of recurrent tonsillitis on growth and cervical lymphadenopathy in children.

A group of 50 children between the ages of 4 and 10 years with a history of recurrent tonsillitis were compared with 50 age- and sex-matched controls. The latter group were recruited from out-patients with orthopaedic, ophthalmological or general surgical problems. The heights and weights of the two groups did not differ significantly. A difference in the incidence of cervical lymphadenopathy between the two groups was demonstrated, but this difference was relatively minor. Of the control children 70% had palpable lymph nodes in their necks. We conclude that none of the 3 factors are of much value in deciding whether or not a patient would benefit from tonsillectomy.

Body Height↗
PubMed1983

Prognostic factors in oral squamous carcinoma and their relation to clinical staging.

One hundred and three patients with an oral squamous carcinoma were studied in an attempt to determine the clinical factors which affect survival. The 5 yr actuarial survival of the whole group of patients was 55%. Although survival depended on clinical staging, in those patients with no palpable nodes on presentation the tumour size did not affect survival. The most significant factor determining survival was the presence of palpable lymph nodes on presentation. Palpable nodes were more likely in patients with large tumours than those with small tumours. On the basis of these findings a modification of the TNM classification is suggested giving more weight to the presence of cervical nodes than in the present staging system.

Adult↗