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Biomedical subjects

D J Webb

Publications and source records attributed to D J Webb.

At least 289 records · Page 16Linked to original sources
PubMed1985

White, exophytic lesion of the left lateral surface of the tongue.

Verrucous carcinoma is an unusual variant of squamous cell carcinoma; it comprises approximately 5% of all oral malignancies. The buccal mucosa, gingiva, and tongue are the most commonly involved areas within the oral cavity. Histologically, verrucous carcinoma can present a diagnostic dilemma. The basement membrane is often intact, which may cause the pathologist to misinterpret these carcinomas as hyperkeratosis and severe dysplasia. The preferred treatment for this lesion is wide local excision. Regional lymph node dissection is usually not necessary and radiation therapy appears to be contraindicated. Close follow-up is recommended.

Carcinoma, Papillary↗
PubMed1985

Expansile radiolucent mass in the maxilla.

The adenomatoid odontogenic tumor is an uncommon, extremely benign odontogenic lesion that should be differentiated from the other osseous lesions. The surgical management should be conservative without expectation of recurrence.

Adolescent↗
PubMed1985

Painful, mixed density mass of the right maxilla.

An additional case of rare, benign osteoblastoma occurring in the right maxilla of a 27-year-old female is reported. The differential diagnosis is discussed and the important distinction between osteoblastoma and low-grade osteosarcoma is stressed.

Adult↗
PubMed1984

Treatment of the odontogenic keratocyst by combined enucleation and cryosurgery.

The treatment of an odontogenic keratocyst of the mandible with a combination of enucleation and cryosurgery has been presented with a 5-year follow-up without recurrence. This case is presented to stimulate interest in the technique and to add a useful option to enucleation alone and enucleation with chemical cauterization. As more cases with long-term follow-up are documented, it is hoped that cryosurgery as an adjunct to enucleation will prove to be a conservative and reliable method of lowering the recurrence rate associated with this lesion.

Cryosurgery↗
PubMed1984

Odontogenic myxoma.

The odontogenic myxoma is a relatively rare benign tumor occurring in the jaws. When the lesion is large and when presenting in a difficult location, aggressive initial therapy affords the most successful outcome. Histologic, radiographic and behavioral characteristics of this rather persistent tumor are briefly reviewed and an approach to diagnosis and definitive treatment of a large maxillary odontogenic myxoma is presented.

Adolescent↗
PubMed1984

Changes in active and inactive renin and in angiotensin II across the kidney in essential hypertension and renal artery stenosis.

Investigations were performed in 26 patients with essential hypertension and 24 with unilateral renal artery stenosis. In each patient blood was drawn simultaneously and in triplicate, from both renal veins and aorta, for measurement of plasma concentrations of active and inactive renin and of angiotensin II. In 19 patients estimates of individual renal plasma flow were obtained in order to calculate secretion rates for active and inactive renin, and to assess the contribution of renin secretion rate and of renal plasma flow to the renal vein renin ratio. In patients with essential hypertension there was evidence that the kidney secreted active renin (18% mean increase in renal vein concentration above that of arterial plasma; P less than 0.001), but no evidence of secretion of inactive renin (4% mean increase; NS). There was a tendency for the kidney to extract angiotensin II (8% mean decrease in renal vein concentration below that of arterial plasma; P = 0.07). The affected kidney in patients with renal artery stenosis showed marked secretion of active renin (364% mean increase; P less than 0.001) and also secreted inactive renin (80% mean increase; P less than 0.05) with net generation of angiotensin II across the renal circulation (100% mean increase; P less than 0.05). The contralateral kidney exhibited suppressed secretion of active renin (3% mean increase; NS) with no evidence of secretion of inactive renin (2% mean increase; NS), and marked extraction of angiotensin II (50% mean decrease; P less than 0.001). The correlation between combined secretion rate of active renin by both kidneys and the arterial concentration of active renin in patients with essential and renovascular hypertension taken together was strongly positive (r = 0.82; P less than 0.01). The same correlation for inactive renin was weak (r = 0.32; NS). The correlation between the combined secretion rates of active renin by both kidneys and the circulating plasma concentration of angiotensin II (r = +0.60; P less than 0.05) was both significant and positive. By contrast, the total 'secretion' rate of angiotensin II by both kidneys was inversely related to arterial plasma angiotensin II (r = -0.92; P less than 0.001). This latter relationship suggests an important role for the kidney in clearing angiotensin II from the circulation, this being more marked the higher the arterial angiotensin II concentration.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Acute, life-threatening disease first appearing as odontogenic pain.

Rapidly spreading rhinocerebral infection by Phycomycetes (mucormycosis) in a diabetic patient with ketoacidosis is described. The dentist and dental specialists should be alert to the early signs and symptoms of this disease as they evaluate and follow patients who are debilitated and who have odontogenic pain. It cannot be overemphasized that a successful outcome is critically dependent on early recognition and prompt therapy, especially in a person with diabetic acidosis as death may occur within 2-5 days after the first symptoms appear.

Acute Disease↗
PubMed1984

Firm swelling on the anterior maxillary gingiva of an infant.

A female infant with a congenital granular cell epulis on the maxillary gingiva has been described. This is consistent with the most common clinical presentation of this lesion. The similarities and differences of this lesion are compared with granular cell tumor.

Female↗
PubMed1984

Enalapril in hypertension with renal artery stenosis: long-term follow-up and effects on renal function.

Enalapril alone, 10-40 mg given once-daily, controlled systemic hypertension long-term (mean follow-up time 19 months) in patients with renal artery stenosis. Significant, but usually modest, increases in serum creatinine and urea were observed. No serious side-effects were seen. A highly significant reduction in peripheral plasma angiotensin II was maintained 24 h after the previous dose of enalapril. Plasma active renin concentration rose 20-fold with long-term enalapril, when the stenotic kidney showed significant secretion of inactive, as well as of active renin. With enalapril therapy, the contralateral kidney showed net extraction of active renin. In unilateral renal artery stenosis, circulation on the affected side is diminished and is mainly via the juxtamedullary nephrons, which become rich in associated renin. Important intrarenal compensatory actions of the renin-angiotensin system include support of glomerular filtration, enhancement of vasa recta-mediated counter-current exchange, sustained urea excretion and maintenance of renal artery pressure distal to the stenosis. These compensatory effects are lost with converting enzyme inhibition. Thus in patients who are candidates for operation, enalapril should usually be given for no more than one month before proceeding to corrective surgery, to allow maximum blood pressure reduction without endangering the stenotic kidney for too long. Enalapril can nevertheless be given effectively long-term in patients unsuitable for corrective surgery.

Adolescent↗
PubMed1984

Renal secretion of inactive renin and extraction of angiotensin II in renal artery stenosis in man: factors determining renal vein renin ratio.

Triplicate blood samples were obtained, without stimulation, simultaneously from the aorta and both renal veins in 24 untreated hypertensive patients with unilateral renal artery stenosis. Across the affected kidney the plasma concentrations of active renin, inactive renin and angiotensin II increased by 363% (P less than 0.001), 80% (P less than 0.05) and 100% (P less than 0.05) respectively. Thus the affected kidney was secreting both active and inactive renin, while appreciable quantities of angiotensin II were generated across the renal circulation on that side. Across the contralateral unaffected kidney there were no significant changes in concentration of active or inactive renin, indicating net suppression of secretion of both forms of renin. Plasma angiotensin II concentration was however markedly reduced, to 50% of the arterial value (P less than 0.001), in the contralateral renal vein, demonstrating renal extraction of angiotensin II. In 14 patients renal plasma flow was also measured. The ratio of active renin concentration between the two renal veins correlated more closely with the renal plasma flow to the affected kidney (r = -0.81; P less than 0.01) than with renin secretion rate on that side (r = +0.37; NS). Thus reduction in renal blood flow rather than increase in renin secretion appeared to be the major determinant of renal vein renin ratio.

Angiotensin II↗
PubMed1983

Factors related to first dose hypotensive effect of captopril: prediction and treatment.

The blood pressure response to the first dose of captopril (6.25 mg, 12.5 mg, or 25 mg) was measured in 65 treated, severely hypertensive patients. Mean supine blood pressure was 187/108 mm Hg immediately before captopril was given. Twenty one patients experienced a fall in supine systolic pressure greater than 50 mm Hg, including five whose pressure fell more than 100 mm Hg and two whose pressure fell more than 150 mm Hg. Six patients developed symptoms of acute hypotension, including dizziness, stupor, dysphasia, and hemiparesis. Percentage reductions in blood pressure were greatest in those with secondary hypertension (p less than 0.05), high pretreatment blood pressure (p less than 0.05), and high concentrations of plasma renin and angiotensin II (p less than 0.01). No significant correlation was found between fall in blood pressure and serum sodium concentration, age, renal function, and the dose of captopril given. A severe first dose effect cannot be consistently predicted in individual patients who have received other antihypertensive drugs for severe hypertension. Such patients should have close medical supervision for at least three hours after the first dose of captopril.

Aged↗
PubMed1981

31P NMR reveals increased intracellular pH after fertilization in Xenopus eggs.

31P NMR spectra of mature eggs of the frog (Xenopus laevis) were taken prior to and after both fertilization and activation by a Ca2+/H+ ionophore (A23187). The eggs were constantly perfused with fresh well-buffered solution during the experiments, and the intracellular pH (pHi) was determined from the pH-dependent chemical shift of the internal Pi peak. The detection of this Pi peak in the presence of overlapping yolk phosphoprotein signals was accomplished by a T2 experiment which discriminated against the broader yolk phosphoprotein peak. The average pHi of the unfertilized, fertilized, and activated eggs was 7.42, 7.66, and 7.64, respectively. Thus, a cytoplasmic alkalinization of 0.24 pH unit occurs within 90 min 90 min after fertilization. These values are practically identical to pHi measurements made in this laboratory on Xenopus eggs by using pH-sensitive glass microelectrodes. These 31P NMR studies also indicate that extracellular pH changes as large as 3 pH units had no effect on pHi. We also found that phosphocreatine levels are very sensitive to metabolic perturbations such as oxygen depletion or metabolic inhibitor application. These treatments resulted in a rapid decrease in the phosphocreatine concentration; the ATP concentration declined only slowly after the phosphocreatine peak had disappeared.

Adenosine Triphosphate↗
PubMed1981

Direct measurement of intracellular pH changes in Xenopus eggs at fertilization and cleavage.

We have used Thomas-type recessed-tip pH-sensitive microelectrodes to measure the intracellular pH (pHi) in Xenopus eggs during both fertilization and ionophore activation. The average pHi in unfertilized eggs is 7.33 +/- 0.11 (SD; n = 21) with a resting membrane potential of -10.1 +/- 3.5 (SD; n = 38) mV. Within 2 min after the onset of the fertilization potential, there is a slight, transient pHi decrease of 0.03 +/- (SD, n = 8), followed by a distinct, permanent pHi increase of 0.31 +/- 0.11 (SD; n = 7) beginning approximately 10 min after the start of the fertilization potential and becoming complete approximately 1 h later. The pHi remains near this level of 7.67 +/- 0.13 (SD, n = 10) through at least 10 cleavage cycles, but it is possible to discern pHi oscillations with a mean amplitude of 0.03 +/- 0.02 (SD, n = 38). Eggs perfused for at least 2 h in Na+-free solution with 1 mM amiloride exhibited all of these pHi changes, so these changes do not require extracellular Na+. Similar cytoplasmic alkalinizations that accompany the activation of metabolism and the cell cycle in a wide variety of cell types are discussed.

Animals↗
PubMed1980

Blood glucose monitors: a laboratory and patient assessment.

The four blood glucose monitors available in the United Kingdom were compared by asking the opinions of 24 patients who used each monitor for two weeks, by correlating their blood glucose results with those obtained in the laboratory, and by having the monitors examined by an electronics engineer. Of the battery-operated monitors, patients preferred the Hypocount (15) to the Glucochek (9). The mains-operated units were less popular, with little to choose between Eyetone and Reflomat. Under field conditions the blood glucose results obtained with the Glucochek correlated poorly with the standard reference method. In contrast the Hypocount, Eyetone, and Reflomat machines produced good correlations. Poor results with the Glucochek were mainly due to faulty timing systems. The patients' preference for the Hypocount was supported by tests of performance under laboratory conditions and by the electronics engineer's report.

Adolescent↗