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Biomedical subjects

S Holt

Publications and source records attributed to S Holt.

215 records · Page 12Linked to original sources
PubMed1970

Mucopolysaccharide in the blood of a patient with neuroblastoma.

In a case of neuroblastoma the presence of an abnormal blood constituent was suspected from the raised erythrocyte sedimentation rate, sludging of the red cells, marked rouleaux formation, an atypical Leishman stain, increased plasma viscosity, and a distorted protein electrophoresis pattern. The abnormal constituent was shown to be a mucopolysaccharide which was either hyaluronic acid or chondroitin sulphate.

Biopsy↗
PubMedDate not supplied

Experimental laser phototherapy of the Morris 7777 hepatoma in the rat.

The tumoricidal effect of the activation of hematoporphyrin derivative (HpD), by an argon-ion-dye-laser (wavelength 630 nm), was investigated in the Buffalo rat bearing subcutaneous implants of the Morris 7777 hepatoma. Tumor growth was monitored by measuring the tumor volume with constant force calipers. In control animals and those that were pretreated with HpD alone (10 or 20 mg per kg by i.p. injection) or laser light alone (2,000 J at 100 mW), a predictable exponential growth pattern of the cancer was observed. Animals were pretreated with HpD (10 mg per kg by i.p. injection) 48 hr prior to the fiberoptic, intratumor delivery of laser radiation (2,000 J at 100 mW), when the tumor had reached a volume greater than 1.5 cm3. Forty-eight hours after combined laser and HpD treatment, the hepatoma underwent coagulation necrosis, and the tumor volume rapidly increased from a mean value of 1.8 +/- 0.7 cm3 S.D. to a value of 5.8 +/- 1.5 cm3 S.D., compared with a mean of 3.7 +/- 0.7 cm3 S.D. in animals who had not received laser phototherapy. Rats treated with HpD and laser light survived longer (mean survival time 48 +/- 12 days S.D.) than did the other animals treated with the laser alone or HpD alone (mean survival time 31 +/- 16.5 S.D.). Tissue biodistribution studies with tritiated hematoporphyrin derivative, given with doses of 10 and 20 mg per kg of HpD, showed higher concentrations of the dye in the liver, kidneys and spleen than in the tumor at 48 hr after administration of the dye.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Facilitation by partial hepatectomy of tumor growth within the rat liver following intraportal injection of syngeneic tumor cells.

The effects of both mechanical trauma and regeneration on the growth of intraportally injected tumor in the rat liver were investigated using two-thirds partial hepatectomy (PH). Tumor grew at the excision scar when PH was performed less than 2 days before tumor injection (34/34 animals). However, when the PH was performed 4-7 days before injection, tumor developed within the regenerating lobe, but not at the scar (50/51). Injecting the same cell dose into rats with intact livers caused few tumors to develop in 12/30 animals. Intraportally injected 51Cr-labelled tumor cells distributed uniformly in the liver irrespective of the time after PH. Patterns of tumor take seen at different times after PH were not due to selective trapping of the injected cells. Liver extracts showed that epidermal growth factor-like activity was unaltered by PH, while heparin-binding growth factor activity peaked at 2 days post-PH, before the incidence of tumor growth in the parenchyma increased. We observed two peaks of DNA synthesis at days 1 and 4 post-PH by pulse labeling with [125I]deoxyuridine and bromodeoxyuridine. Bromodeoxyuridine immunohistochemistry showed the first peak to be confined to hepatocytes. The second peak involved non-hepatocytes and coincided with the beginning of enhanced tumor take in the regenerating lobe.

Animals↗
PubMedDate not supplied

Measuring synaptosomal associated protein-25 kDa in human cerebral spinal fluid.

Changes in the quantity and distribution of neuronal proteins have been reported in psychiatric and neurological illnesses. The majority of this work has been performed in post-mortem samples and the results are difficult to apply to clinical care. The objective of this study is to develop a methodology that can identify trace amounts of brain proteins in cerebral spinal fluid (CSF). Human cerebral spinal fluid was processed to remove albumin and immunoglobulins. CSF samples were analyzed on Western blots using a monoclonal antibody against SNAP-25. These samples were compared to SNAP-25 immunoprecipitated from CSF, rat and human brain homogenates. The monoclonal antibody Mab 331 identified a single band of 25 kDa in all samples. These results demonstrate that the presynaptic protein SNAP-25 can be identified and measured in CSF.

Animals↗
PubMedDate not supplied

Pathogenesis of renal failure in rhabdomyolysis: the role of myoglobin.

Rhabdomyolysis causes renal dysfunction associated with renal vasoconstriction, tubular toxicity and luminal obstruction. There is now accumulating evidence that renal injury, caused by lipid peroxidation, is important in the pathogenesis of renal failure. The proposed central role of free iron in this process is examined. Current data have shown that the heme center of myoglobin can initiate lipid peroxidation and renal injury without invoking release of free iron, and this process is due to redox cycling of the heme group from ferrous to ferric and to ferryl oxidation states. Alkaline conditions prevent myoglobin-induced lipid peroxidation by stabilizing the reactive ferryl myoglobin complex. This review explores the evidence for each of these mechanisms.

Animals↗
PubMedDate not supplied

Can the presence of equinus contracture be established by physical exam alone?

The condition in which ankle dorsiflexion is restricted is known as equinus contracture (EC). Equinus contracture is purported to be associated with a number of clinical conditions. However, there are no data to support or refute a clinician's ability to diagnose EC by clinical exam. We prospectively evaluated the maximum ankle dorsiflexion with the knee fully extended in 68 people (34 patients with isolated fore- or midfoot pain and 34 asymptomatic subjects) both by clinical exam and by a custom-designed ankle goniometer. We compared the likelihood of agreement of the clinical impression (equinus, no equinus) to the maximum ankle dorsiflexion measured with the instrument at two different numerical definitions of EC (< or =5 degrees and < or =10 degrees of maximum dorsiflexion). When all subjects were included and equinus defined as < or =5 degrees of ankle dorsiflexion, a clinician's ability to detect the equinus when it is truly present is 77.8%. If equinus is defined as < or =10 degrees, this ability increases to 97.2%. Alternatively, if equinus is not present, as defined by < or =5 degrees, then a clinician's ability to correctly diagnose no equinus is 93.8%. If equinus is defined to < or =10 degrees, this ability decreases to 68.8%.

Adult↗
PubMedDate not supplied

Genetics of gastric cancer.

Although the death rate from gastric carcinoma in the US and other western communities has decreased in recent times, a similar trend has not been noted in other countries, especially S.E. Asia. Upto 95% of all malignant gastric neoplasms are adenocarcinomata, but other types of gastric cancer have evoked considerable interest in the literature. Genetic factors have been suspected of playing a pivotal role in the etiology of gastric cancer but no clear inheritance pattern has emerged and environmental influences remain the focus of many current theories of pathogenesis. Current evidence implicates the non-random involvement of certain chromosomes and related oncogenes especially Ras and p53. Genes that may predispose to gastric cancer have not been clearly implicated but some studies indicate a familial aggregation of gastric cancer. The objective of this review is to reappraise the role of genetics in the etiology of gastric cancer with special reference to relevant information for practicing clinicians.

Animals↗