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Biomedical subjects

M Schaffer

Publications and source records attributed to M Schaffer.

29 records · Page 2Linked to original sources
PubMed1988

Quantitative determination of Escherichia coli from faecal coliforms in seawater.

A simple rapid method was developed for counting Escherichia coli in sea water using a membrane filter procedure. Following filtration the membrane filter was incubated on mFC agar medium for 24 +/- 2 h at 44.5 +/- 0.2 degrees C for determination of faecal coliforms. An in situ test for the determination of E. coli was carried out by transferring the membrane filter to nutrient agar containing 4,methyl-umbiliferyl-B-D, glucoronide, followed by incubation for 3 h at 35 degrees C. The E. coli colonies were detected by fluorescence under long wavelength UV light. Extensive biochemical confirmation tests on the isolates showed that all the fluorescence colonies which were either lactose positive or negative were E. coli.

Enterobacteriaceae↗
PubMed1986

A simple method for counting Staphylococcus aureus in swimming pool water.

Staphylococcus aureus counts from swimming pool water were determined by the membrane filtration technique. Water samples were passed through a membrane filter and then put on Baird-Parker media. After incubation, the filters were transferred to nutrient agar, and incubated at 37 degrees C, for 3 h. After removal of the filters, the plates were incubated at 60 degrees C for 2 h. An overlay of toluidine blue agar was added and the plates reincubated for 4 h at 37 degrees C. The formation of thermonuclease correlated with the formation of coagulase, and the results indicated that Staphylococcus aureus could be present in swimming pool water without the presence of either coliform or faecal coliform bacteria.

Enterobacteriaceae↗
PubMed1985

Neuropeptide function: the invertebrate contribution.

The following is a list of generalizations that arise from considering the present state of knowledge concerning the functions of invertebrate peptides. Some of these clearly also apply to vertebrates. Invertebrate peptides can be classified into structurally related groups. Structural similarity of peptides may represent true evolutionary homology by selection acting on an original gene. Alternatively, independent evolution of similar genes may have occurred because certain amino acid sequences represent optimal solutions to complex functional problems. Invertebrate neuropeptides have multiple functions. Thus, proctolin is a cardioactive peptide, a skeletal neuromuscular transmitter, a hindgut neuropeptide, a peptide of CNS interneurons (Keshishian & O'Shea 1984) and may have humoral roles. Invertebrate peptides act through a variety of molecular mechanisms. Generalizations about the mechanism cannot yet be made. Thus, proctolin's action on crustacean skeletal muscle is not associated with stimulation of cyclic-AMP or protein phosphorylation, but the action of SCPB on molluscan skeletal muscle involves elevation of cAMP. Invertebrate peptide inactivation can be caused by proteolysis that can also function to enhance peptide bioactivity. Proctolin is made virtually biologically inactive by any proteolysis, but alpha-BCP bioactivity is enhanced by two steps of carboxy peptidase digestion before being functionally inactivated. Protease action on released peptides is not necessarily a "simple" form of transmitter inactivation. Protease action also involves functional processing whereby the temporal and spatial parameters of a peptide's action may be shaped. Invertebrate neuropeptides are frequently co-localized with other neuroeffectors. Peptides may be co-localized and released with other active peptides as in the bag-cell example, or may be coactive with more conventional transmitters, as in the Ds motoneuron example. In such circumstances there is no reason to view either transmitter as primary or secondary. Invertebrate neuropeptides are widely involved in the control of muscle contraction. These effects may be locally and directly mediated as in the Ds motoneuron example or may be humoral. The peptide may act directly on the muscle contractile system or function to modulate the muscles' response to other motor input. Muscle contraction may be induced by a neuropeptide without depolarization of the muscle cells, for example see proctolin. Invertebrate neuropeptides are frequently involved in the control of oscillatory functions. In several examples peptides activate rhythmic myogenic contractions of cardiac and skeletal muscle.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1984

Fatal maprotiline intoxication.

We report a fatal case of drug toxicity associated with torsade de pointes following an overdose of the tetracyclic antidepressant, maprotiline (Ludiomil). Tissue and plasma levels were obtained at autopsy and are noted. In addition, the cardiovascular effects, pharmacokinetics, and toxicity of maprotiline are reviewed and compared with that of tricyclic antidepressants.

Adult↗
PubMed1984

Isolation and characterization of two myoactive neuropeptides: further evidence of an invertebrate peptide family.

The neuropeptide proctolin acts as a neuromuscular co-transmitter in insect skeletal muscle. As a prelude to determining whether other peptides may function in a similar way, we are attempting to isolate and characterize the chemical nature of new myoactive neuropeptides in insects. We examined the corpus cardiacum, a major insect neurosecretory structure of the American cockroach (Periplaneta americana), using a skeletal muscle bioassay and high pressure liquid chromatography fractionation and identified two myoactive factors, MI and MII. They are synthesized in the corpus cardiacum and released from it into the blood by a calcium-dependent mechanism. Amino acid and fast atom bombardment-mass spectroscopy analysis show that MI and MII are structurally related octapeptides representing the major secreted products of the cockroach corpus cardiacum. Both MI and MII are also present in the CNS and in the gut, indicating transmitter as well as hormonal functions in the cockroach. A survey in other species indicates MI may be present in invertebrates other than insects, but neither was found in the rat. The MI and MII peptides have clear chemical affinities to two previously described invertebrate peptides, locust adipokinetic hormone and crustacean red pigment concentrating hormone, as well as sharing biological activity with these peptides. Our results provide further evidence for the existence of a large family of structurally related peptides with divergent functions in a variety of invertebrate types.

Animals↗
PubMed1983

Morphologic and morphometric studies of muscle in idiopathic scoliosis.

The gluteus maximus and paraspinal muscles in 15 cases of idiopathic scoliosis at the apex of the curve showed myopathic changes and a significant decrease in the type II fibers. Fiber type II atrophy was observed only on the concave side. Ultrastructure of paraspinal and gluteus muscle biopsies showed disruption of myofilaments, Z band streaming and subsarcolemmal accumulation of glycogen, lipid and mitochondria. Quantitative estimation of these subcellular organelles pointed out that a higher glycogen content was significant in both paraspinal as well as the gluteus muscles while a higher mitochondrial content was significant only on the convex side and the gluteus muscle but not the concave side of the apex when compared to normal quadriceps muscle. These findings suggest that idiopathic scoliosis is a diffuse disease process and may be considered a primary muscle disease.

Adolescent↗
PubMed1980

A comparison of enzyme immunoassay and gas chromatography/mass spectrometry in forensic toxicology.

A series of 137 urine samples were analyzed for drugs of abuse by enzyme immunoassay (EMIT) and by gas chromatography/mass spectrometry (GC/MS). Agreement between these methods was excellent and ranged from 93.4% for benzodiazepines to 98.5% for propoxyphene. EMIT false negative were traced to the presence of elevated endogenous lysozyme or other interfering materials. In the case of moderate amounts of lysozyme the use of a blank would lead to correct results. Disagreement in the identification of nine benzodiazepine samples was found to be due to a low recovery of benzodiazepine metabolites from urine. Recovery could be improved by incubation of the urine sample with the enzyme beta-glucuronidase.

Benzodiazepines↗
PubMed1976

Effect of protein intake and dialysis on the abnormal growth hormone, glucose, and insulin homeostasis in uremia.

UNLABELLED: To evaluate the role of protein intake in the altered growth hormone (GH) secretion of chronic renal failure, GH responses to mild exercise and to an oral glucose tolerance test were measured in ten uremic patients ingesting both low and normal protein diets. To delineate the effect of uremia on any interaction between GH and protein intake, tests were performed before dialysis, after daily dialyses for 3-4 days and after withholding dialysis for 3-4 days. Results were as follows: (1) exercise-stimulated GH release was increased compared to controls; (2) protein intake did not alter GH secretion, (3) basal GH concentrations were significantly correlated with creatinine levels and were significantly lower after dialysis, (4) dialysis did not improve the oral glucose tolerance test, (5) there was no correlation between glucose tolerance and exercise-stimulated GH levels, basal GH concentrations, or the sum of GH values after glucose, and (6) dialysis significantly increased the insulin response to glucose. CONCLUSIONS: In chronic renal failure enhanced GH secretion is not affected by protein intake, does not cause glucose intolerance, and may be related to the degree of uremia. Dialysis does not improve glucose tolerance, but does increase glucose-stimulated insulin release suggesting that insulin antagonism is not ameliorated.

Adult↗
PubMedDate not supplied

Results of postoperative radiotherapy of cervix carcinoma after radical versus non radical hysterectomy.

UNLABELLED: We studied the outcome of our 68 cervix carcinoma patients treated either with: 1) radical surgery and postoperative 192Ir high-dose rate afterloading brachytherapy or postoperative radiotherapy to the whole pelvis or with 2) standard hysterectomy and postoperative radiotherapy to the whole pelvis. Forty-eight women were treated by radical hysterectomy from 1988 to 1992 and--due to risk factors--by postoperative radiotherapy (Group 1), 20 other patients (Group 2) pretreated with standard hysterectomy were admitted to the university hospital for postoperative radiotherapy of the whole pelvis. Postoperative radiotherapy consisted of 39.6 Gy total dose using the box technique, plus two afterloading applications with a single dose of 7.5 Gy and 6 Gy external beam therapy to the pelvic lymph nodes sparing the midline. Comparing the Kaplan-Meier plots of both groups, the tumor related survival curve, the locoregional control and the rates of metastatic disease were nearly identical. But in the analysis of special subgroups, patients with positive lymph nodes after standard hysterectomy and postoperative radiotherapy had a worse prognosis (75% three years' survival rate) than patients after radical surgery (86% three years' survival rate). Lymphangiosis was a negative prognostic factor for the patients pretreated with standard hysterectomy (60% versus 80% three years' survival rate), but not for patients after radical surgery (80% three years' survival rate), despite the same radiotherapy in both groups. CONCLUSION: Standard hysterectomy fails to be an adequate treatment for early cervix carcinoma because moderately dosed postoperative radiotherapy cannot achieve complete locoregional control in all cases of positive lymph nodes or invasion of lymph vessels. However, based on the empirical results of many authors and our own results, postoperative radiotherapy is further indicated in high risk cases of cervix carcinoma after radical surgery.

Female↗