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L Matz

Publications and source records attributed to L Matz.

12 recordsLinked to original sources
PubMed2001

Electrospray ionization high-resolution ion mobility spectrometry for the detection of organic compounds, 1. Amino acids.

Our aim in this investigation was to demonstrate the potential of the high-resolution electrospray ionization ion mobility spectrometry (ESI-IMS) technique as an analytical separation tool in analyzing biomolecular mixtures to pursue astrobiological objectives of searching for the chemical signatures of life during an in-situ exploration of solar system bodies. Because amino acids represent the basic building blocks of life, we used common amino acids to conduct the first part of our investigation, which is being reported here, to demonstrate the feasibility of using the ESI-IMS technique for detection of the chemical signatures of life. The ion mobilities of common amino acids were determined by electrospray ionization ion mobility spectrometry using three different drift gases (N2, Ar, and CO2). We demonstrated that the selectivity can be vastly improved in ion mobility spectroscopy (IMS) in detecting organic molecules by using different drift gases. When a judicial choice of drift gas is made, a vastly improved separation of two different amino acid ions resulted. It was found that each of the studied amino acids could be uniquely identified from the others, with the exception of alanine and glycine, which were never separable by more then 0.1 ms. This unique identification is a result of the different polarizabilities of the various drift gases. In addition, a better separation was achieved by changing the drift voltage in successive experimental runs without significantly degrading the resolution. We also report the result of our analysis of liquid samples containing mixtures of amino acids.

Amino Acids↗
PubMed1999

High prevalence of osteoporosis in cardiac transplant recipients and discordance between biochemical turnover markers and bone histomorphometry.

OBJECTIVE: All patients attending the cardiac transplantation clinic at the Royal Perth Hospital were investigated to determine the prevalence of osteoporosis and to assess changes in bone metabolism and histomorphometry in a cohort of cardiac transplant recipients. DESIGN: Retrospective cross-sectional study. PATIENTS: Thirty-two patients (27 male; 5 female) who had received a cardiac transplant during the past 10 years and who were receiving immunosuppressive therapy with cyclosporin, azathioprine and prednisolone were studied. MEASUREMENTS: All patients had bone densitometry by DEXA of the lumbar spine and femoral neck and X-rays of the thoracolumbar spine. Fasting serum ionized calcium, intact PTH, creatinine, 25 hydroxy-vitamin D, alkaline phosphatase, osteocalcin, testosterone and free thyroxine and urine calcium, creatinine, hydroxyproline and deoxypyridinoline were measured. Six osteoporotic patients consented to transiliac bone biopsy following double tetracycline labelling. RESULTS: Osteoporosis was present at the lumbar spine in eight patients, femoral neck in seven patients and was present at one or more sites in 13 patients (41%). Seven patients (22%) had vertebral fractures which were asymptomatic in five patients. Secondary hyperparathyroidism was present in 16 patients (53%) but significant renal failure (creatinine clearance < 70 ml/min) was only found in 8 (50%). Levels of biochemical markers of bone turnover were increased in 23 patients (72%). Serum osteocalcin (P = 0.02) and alkaline phosphatase (P = 0.04) were significantly higher in osteoporotic patients than in nonosteoporotic patients. Histomorphometric findings varied markedly between patients. Microscopic features of hyperparathyroidism were not observed. CONCLUSIONS: Osteoporosis and asymptomatic vertebral fractures are common following cardiac transplantation. Biochemical markers of bone turnover were increased in the majority of patients. Many had biochemical evidence of secondary hyperparathyroidism but this could be attributable to significant renal failure in only 50% of cases. Osteocalcin and alkaline phosphatase correlated inversely with bone density. Histomorphometric findings did not correlate with these biochemical changes in most cases. These results suggest that multiple factors are responsible for osteoporosis in cardiac transplant recipients. Osteocalcin and alkaline phosphatase may be useful biochemical markers, predicting patients at highest risk of fracture.

Adult↗
PubMed1992

Flexible sigmoidoscopy screening in an industrial setting.

Little is known about the yield of colorectal cancer screening programs in an industrial setting. We therefore established a flexible sigmoidoscopy screening program at a chemical manufacturing plant and offered testing to all employees over the age of 40. After a Fleet enema preparation had been administered, a digital rectal examination and sigmoidoscopy were performed on each volunteer worker in the medical office of the plant. The plant had an average census of about 650 workers; 202 were screened during a 2-yr period. The mean (+/- SEM) age of participants was 52 +/- 0.4. Sixty-four employees had polyps (31.7%); data on follow-up colonoscopy were available in 69%. Colonoscopy revealed adenomatous polyps in 23 workers (53.5%), hyperplastic polyps in 10 (23%), and no evidence of neoplasia in 10 (23%). Seven workers did not arrange for follow-up colonoscopy and 12 individuals could not be contacted. No cancers were detected. In the 40- to 50-yr age group, polyps were detected in 19.5% of employees (25% adenomatous). Incidental findings were common, and included prostatic nodules, hemorrhoids, diverticulosis, and proctitis, among others. We conclude that screening sigmoidoscopy can be conveniently and economically performed at the workplace, with a high yield and good worker acceptance. The high yield suggests a possible association between polyp formation and work in a chemical plant. The finding of adenomatous polyps in the younger patients suggests that the threshold for flexible sigmoidoscopy at age 50 needs to be reassessed.

Adult↗
PubMed1990

Tolerance of the liver to the effects of Yttrium-90 radiation.

There are no reliable data documenting the tolerance of the human liver to ionizing radiation from a continuous Yttrium-90 source. As Yttrium-90 incorporated into microspheres is being used to treat patients with liver cancer, it is imperative that the tolerance of the human liver to this form of radiation damage be determined. Four patients with metastatic liver cancer were treated with Yttrium-90 to deliver radiation doses above that considered tolerable when given by conventional external sources. Patients were monitored with serial estimations of liver function tests and between 7 and 9 months after treatment liver biopsies were performed. Histological examination of the liver biopsies confirmed only minimal changes in the normal liver parenchyma. These data indicate that the human liver may tolerate relatively large radiation doses when delivered by Yttrium-90 microspheres embedded in the liver parenchyma as a number of discrete point sources.

Adenocarcinoma↗
PubMed1989

Malignant paraganglioma causing bilateral pleural effusions.

A male patient presented with dyspnea due to a large left pleural effusion, and pleural biopsy revealed a malignant paraganglioma. Raised urinary catecholamine levels confirmed a functioning tumour. Aggressive local spread occurred which did not respond to cytotoxic chemotherapy. The primary site of the tumour was most likely the aorticosympathetic chain.

Aged↗
PubMed1985

Juxtaglomerular tumour: diagnostic renal vein renin measurements obscured by chronic captopril therapy.

A case of juxtaglomerular tumour (sometimes called hemangiopericytoma) in a 17 year old boy, presenting with severe hypertension and hypokalemia, is described. Plasma renin activity was markedly elevated in both renal veins and failed to lateralise the tumour. This is attributed to chronic stimulation of renin secretion by Captopril treatment. Removal of the tumour cured the hypertension and hypokalemia.

Adolescent↗
PubMed1981

Effective of acetylsalicylic acid, indomethacin, phenylbutazone, paracetamol, ibuprofen and naproxen on canine gastric mucosa: a histological and ultrastructural study.

The effect of various non-steroidal analgesic drugs on gastric mucosal cells was studied in 48 dogs with 2 other dogs as control. Each drug was instilled into the stomach of 8 anaesthetised dogs through a gastrostomy. Gastric biopsies, obtained at 0, 1, 2 and 3 hours after administration of the drug, were subjected to histological and electron microscopical examination. Histological analysis did not show any significant changes in gastric mucosal cells in any of the drug-related groups as compared to controls. Electron microscopy, however, showed significant changes in the gastric mucous cells and parietal cells of all test groups, as compared to controls. Ultrastructural abnormalities in mucous cells included dilation of cisternae of endoplasmic reticulum, loss of granules and microvilli, and thickening of the mucous layer and were most pronounced with acetylsalicylic acid, moderate with phenylbutazone, indomethacin and naproxen, but mild with paracetamol and ibuprofen. Parietal cell changes consisting of reduction in the concentration of tubulovesicles, which canaliculi, were found to be severe with indomethacin and phenylbutazone, moderate with paracetamol and naproxen, but only minimal with acetylsalicylic acid and ibuprofen.

Acetaminophen↗