Search PubMed⌕ Search

Biomedical subjects

R David

Publications and source records attributed to R David.

At least 217 records · Page 12Linked to original sources
PubMed1979

Radiotherapeutic agents: properties, dosimetry, and radiobiologic considerations.

Radioactive nuclides for treatment have occupied an important but somewhat diminishing role in the total practice of nuclear medicine. Although theoretically they should have important potentialities, particularly in the treatment of various forms of cancer, their development in this field has not kept pace with the progress in other treatment modalities in radiation oncology. Indications for the selection of appropriate isotopes for therapy revolve about the emission of beta particles of sufficient energy, which are administered in a chemical form that reaches the tumor. Methods of calculation of doses delivered to sites of deposition are discussed in the text. Radiobiologic considerations include the possibility of early deleterious effects from overdosage, and consideration of chromosomal changes of circulating lymphocytes and their implications. Late effects that have been of great public concern are confined almost solely to possible carcinogenesis, and this effect has been minimal in patients receiving therapeutic levels of radioactive drugs. Genetic and developmental effects, also, have been negligible. Complications encountered more frequently have been leukemia after extensive therapy of thyroid carcinoma, and local fibrosis after direct injection of radioactive colloids into tumor tissue.

Adolescent↗
PubMed1979

Unilateral enlargement of the masseter muscle.

Benign hypertrophy of the masseter muscle is a relatively uncommon condition which may occur unilaterally or bilaterally. The etiology of the ailment is unclear in the majority of cases, and the histopathological features are usually those of normal muscle. A case of unilateral masseter muscle enlargement is described in a 19-year-old Arab male. The histopathological findings were compatible with a mild myopathic disorder. The characteristics, differential diagnosis, etiology, treatment and histopathological features of masserteric hypertrophy are discussed.

Adult↗
PubMed1979

Lipofuscin in human tongue muscle.

In a study of 107 tongue specimens lipofuscin granules were found to be present in the muscle fibers of 93% of the cases. The pigment was not found in young individuals under the age of 18 years. The pigmented granules, which were stored in clusters of different sizes at the nuclear poles, were PAS-positive, stained black or brown with the Masson-Fontana procedure, black with Sudan black, and strong purple-pink with Ziehl-Neelson staining; yellow autofluorescene was emitted in ultraviolet light. The morphology, histochemical reactions and autofluorescence of the pigmented granules were characteristics of the endogenous lipid pigment described as lipofuscin. Statistical analyses indicated a direct correlation between increase in quantity and distribution of the pigment and increase in age (P = 0.001), in both males and females. Accumulation of the pigment in the tongue with aging was found to be similar to that in the myocardium.

Adolescent↗
PubMed1979

HLA antigens in glaucoma and ocular hypertension.

Forty-five white patients (32 with open-angle glaucoma and 13 with ocular hypertension) and 63 black patients (41 with open-angle glaucoma and 22 with ocular hypertension) were tissue typed for a total of 38 HLA antigens and the results compared to normal, unrelated, panels of 248 white donors and 150 black volunteers, respectively. No statistically significant differences with regard to the frequencies of 38 HLA antigens were detected among the various groups.

Black People↗
PubMed1979

Surgical treatment for pneumatosis cystoides intestinalis complicating jejunoileal by-pass.

A case of chronic pneumatosis cystoides intestinalis, complicating jejunoileal by-pass procedure for morbid obesity, is described. Grave clinical symptoms associated with irreversible segmental mucosal atrophy and mural fibrosis resulting from untreated long-standing pneumatosis intestinalis, required resection of the whole by-passed small intestine. It is suggested that this simple and safe surgical procedure is justified in selected cases. Conservative treatment of asymptomatic patients with pneumatosis intestinalis, however, may prevent further surgical intervention in these patients.

Adult↗
PubMed1978

Increased glomerular filtration rate in patients with major burns and its effect on the pharmacokinetics of tobramycin.

The clearance of endogenous creatinine in 20 burned patients, measured between the fourth and the 35th post-burn day, was a mean (+/- S.D.) of 172.1 p 48.4 ml per minute per 1.73 m2; in eight normal subjects the mean value was 125.4 g- 10.4 (P less than 0.02). Thirteen patients had values more than 2 S.D. above the normal mean. We confirmed this rise in glomerular filtration rate by measuring inulin or iothalamate clearance in nine patients. The pharmacokinetics of tobramycin were studied in 11 of the 20 patients and in eight normal subjects receiving continuous intravenous infusions of the drug. An inverse correlation was found between plasma half-life of the drug and creatinine clearance (r = 0.68, P less than 0.01). Increased creatinine clearances and shortened half-life of tobramycin occurred mainly in younger patients. Glomerular filtration rates in burned patients may rise to very high values and can be validly measured by creatinine clearance. The plasma half-lives of drugs with predominantly urinary excretion may decrease in patients with burns.

Adult↗
PubMed1978

Amyloid stroma in a tubular carcinoma of palatal salivary gland: a histochemical and ultrastructural study.

Amyloid as defined by positive Congo red green birefringence and STB red birefringence was observed in the stroma of a tubular carcinoma of minor salivary gland origin. The amyloid exhibited additional histochemical characteristics of immunamyloid, viz., positive DMAB-nitrate and DC-reactions and spontaneous autofluorescence. Electron microscopic studies of the epithelial tumor cells displayed large amounts of cytoplasmic microfilaments similar to those present in the extracellular amyloid masses. It is suggested that the amyloid is derived from spontaneous assembly or polymerization of cytoplasmic microfibrils of the dying tumor cells as has been proposed for the amyloid associated with the calcifying epithelial odontogenic tumor (CEOT).

Adenocarcinoma↗
PubMed1978

Corpora amylacea in mesothelioma of the atrioventricular node.

Rounded or polyhedral, acellular, dense lamellated structures were seen within gland-like spaces in a case of atrioventricular mesothelioma. These structures exhibited many of the histochemical characteristics of amyloid, viz., pink colour with green birefringence and bright red fluorescence with alkaline Congo red; ortochromasia and red birefringence with standardised toluidine blue; positive DMAB-nitrite and diazotisation coupling reactions and spontaneous autofluorescence. It is suggested that these bodies are derived from spontaneous assembly or polymerisation of microfibrils of desquamated cells lining the cystic spaces of the tumour as occurs in prostatic corpora amylacea. The peculiar intramyofibre proliferation of tumour cells in the peripheral part of the tumour suggests that viable tumour cells can penetrate, survive and proliferate within atrial or nodal myofibres leaving an intact sarcolemmal sheath. The slow tumour cell growth and the successive degeneration of central tumour cells may explain the tubular and/or glandular pattern constantly seen in this tumour.

Aged↗
PubMed1978

Lipofuscin in salivary glands in health and disease.

Lipofuscin granules were observed in normal salivary glands (parotid, submandibular, and minor salivary glands). The pigment was confined mainly to the epithelial cells of the intralobular ducts, but isolated granules were also found in acinar cells and myoepithelial cells. In chronic sialadenitis pigment granules were found in the intralobular epithelial cells and in macrophages in the surrounding ionnective tissue. In benign epithelial tumors pigment granules were observed within neoplastic epithelial cells and in macrophages in the stroma, while malignant tumors displayed pigmented granules only in macrophages in the stroma.

Adenoma, Pleomorphic↗
PubMed1978

Corpora amylacea in adenolymphoma (Warthin's tumor).

Round or polyhedral, acellular, lamellated or amorphous eosinophilic structures were observed in the cystic spaces of adenolymphomas. These eosinophilic bodies ahd several of the histochemical characteristics of amyloid, viz., pink color with green specific birefringence and bright red fluorescence with alkaline Congo red; positive DMAB-nitrite and DC reactions, and spontaneous autofluorescence. It is suggested that these bodies are derived from spontaneous assembly or polymerization of microfibrils of desquamated epithelial cells lining the cystic spaces of the tumor, as has been described to occur in prostatic corpora amylacea.

Adenolymphoma↗
PubMed1978

Lipopigment in odontogenic cysts.

A study of 105 odontogenic cysts revealed the presence of pigmented cells in the cyst wall in 38% of the cases. The frequency of pigmented cells was higher in the inflammatory odontogenic cysts than in the development cysts. Although isolated pigmented cells were seen within the epithelial lining and cyst cavity, the larger collections were closely associated with cholesterol crystals and hemosiderin deposits; they contained light brown cytoplasmic pigment which manifested sudanophilia, acid-fastness, silver reduction capacity, PAS positivity and yellow autofluorescence in ultraviolet light. The morphology, histochemical reactions and autofluorescence suggest that the pigmented cells are macrophages containing ceroids. It has been suggested that the hemosiderin which is found in the cyst wall serves as an oxidation catalyst for the locally liberated lipids, the end result of which is the formation of the ceroid pigment.

Cholesterol↗
PubMed1978

Ocular hypertension: a comparative follow-up of black and white patients.

Forty-four eyes in 25 black patients are compared with 92 eyes of 47 white patients in a population with ocular hypertension followed up for 1 to 12 years in a glaucoma clinic. The black patients present at a younger age than the whites and their mean initial intraocular pressure is significantly higher. The fact that more black ocular hypertensives developed glaucoma--8 eyes (18.1%) in the black population as compared with 5 eyes (5.4%) in the white population--is attributed to these two differences.

Adult↗
PubMed1978

Follow-up of aphakic patients with anterior vitrectomy in one eye and uneventful cataract extraction in the fellow eye.

Twenty patients had operations for bilateral cataract in 2 separate sessions, with uncomplicated extraction on one side and vitreous loss managed with anterior vitrectomy on the other. The cataracts, the type of surgery, and the postoperative treatment were identical in both eyes. The differences between the 2 eyes were not statistically significant so far as the amount of astigmatism, final visual acuity, and peripheral anterior synechiae were concerned. The main difference was found to be the period of time the vitrectomised eyes remained red and uncomfortable as compared to the eyes with uncomplicated surgery.

Aged↗
PubMed1978

Aniridia associated with microcornea and subluxated lenses.

Four cases of aniridia associated with subluxated lenses and microcornea are presented. The triad occurred in both eyes of the 4 affected members in one Ndebele family (one of the South African Negro tribes). No other ocular or systemic defects were noted, and intelligence was normal. Chromosomal studies on both parents showed no abnormality, and gene marker studies failed to reveal any linkage between the disease locus and a wide range of polymorphic loci.

Adolescent↗