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D Fitzpatrick

Publications and source records attributed to D Fitzpatrick.

At least 109 records · Page 6Linked to original sources
PubMed1981

Effect of Ca++ on triphosphoinositide extraction in fusing myoblasts.

Ca++-dependent degradation of triphosphoinositide has been postulated to regulate levels of membrane-bound Ca++ and to generate a 1,2-diacylglycerol fusogen in cell fusion. Triphosphoinositide metabolism was therefore studied during Ca++-induced fusion of cultured chick embryo myoblasts. Using a frequently cited extraction procedure, it was found that apparent Ca++-dependent triphosphoinositide degradation was actually due to inhibition of extraction. A new procedure using the ion-pairing reagent tetrabutylammonium sulfate was developed which was unaffected by Ca++ and gave 2- to 20-fold greater extraction of triphosphoinositide than existing procedures. With this procedure, no changes in triphosphoinositide metabolism were found during myoblast fusion.

Animals↗
PubMed1980

Distribution of acetylcholinesterase in the geniculo striate system of Galago senegalensis and Aotus trivirgatus: evidence for the origin of the reaction product in the lateral geniculate body.

This inquiry began with the discovery that just two layers of the lateral geniculate nucleus (GL) of Galago contain large amounts of acetylcholinesterase (AChE). These two layers (layers 3 and 6) are similar in cell size and Nissl-staining characteristics and project to the same layer in the striate cortex. To find out whether the pattern of staining is unique in the Galago, we examined the distribution of AChE in the lateral geniculate nucleus of the owl monkey, Aotus trivirgatus. In this species we found that the parvocellular layers (3 and 4) stained darkly for AChE while the magnocellular layers (1 and 2) were only slightly stained. The interlaminar zones as well as the "S" layers were also distinguished by a high level of AChE staining. In order to determine the source of the cholinesterase staining in layers 3 and 6 of Galago, we studied, in separate experiments, the effects of kainic acid injections into GL, of eye enucleation, and of lesions of the striate cortex. Injections of kainic acid, followed by survival times of 2 and 11 days, produced severe cellular destruction in GL, yet the AChE staining of layers 3 and 6 was undiminished. Eye enucleations had no effect upon the AChE staining of GL even after a survival period of 3 years. In contrast, a small lesion of the striate cortex, followed by a 9-day survival period, produced conspicuous gaps in the AChE staining of layers 3 and 6. These results indicate that the AChE in layers 3 and 6 is not attributable to the cells within the layers, or to retinal fibers, but is dependent upon descending projections from the striate cortex. Because of the dependence of the AChE reaction product in layers 3 and 6 of GL upon an intact striate cortex, we turned our attention to the distribution of AChE in the striate cortex. In Galago, cholinesterase-positive cells were found in layer VI of the striate cortex; and in both Galago and Aotus, the striate cortex was distinguished from other cortical areas by a prominent band of cholinesterase activity within layer IV. This band ended abruptly at the 17-18 border. The precise origin of this cholinesterase staining within layer IV of the striate cortex remains to be determined.

Acetylcholinesterase↗
PubMed1980

Use of monocytes in HLA-A, B, C and DR typings.

A simple method of improved serologic typing of monocytes for HLA-A, B, C and DR specificities is described. The method employs monocytes recovered from frozen samples of peripheral blood mononuclear cells; it chiefly involves pretreatment of monocytes with 0.01% iodoacetamide (IAA) prior to typing. The advantage of this method lies principally in the lowering of the background nonspecific cytotoxicities and false positive readings upon IAA addition to the monocyte preparations. Using this method monocytes can be typed for HLA-A, B, C determinants. Although the addition of IAA results in substantial typing improvements, we found the assignment of A, B, C specificities difficult due to the presence of extra positive reactions when monocytes were compared to T lymphocyte typings. probably due to the presence of DR or monocyte specific antibodies in the routinely used HLA antisera. This method proved to be most useful in DR typings where mono cytes in the presence of IAA were compared with autologous B cells in the absence of IAA. The differences in typings due to a decrease in false positive cytotoxic readings were significantly in favor of using IAA treated monocytes in DR typings (P < 0.0001). The use of IAA in the course of B cell or T cell typings bad no adverse consequences on either A, B, C or DR typings, respectively. Our results indicate a potential usefulness for the use of IAA in typing monocytes HLA determinants in general and for the DR determinants in particular.

Enzyme Inhibitors↗
PubMed1980

The Mitchell distal metatarsal osteotomy for hallux valgus.

Seventy-two Mitchell distal metatarsal osteotomies for hallux valgus performed over a period of 10 years have been reviewed. Sixty-six (92 per cent) were graded as excellent or good. Retrospective radiographic analysis of 29 of these cases showed that the operation had reduced the intermetatarsal angles to within normal anatomical limits. No patient experienced a worsening of symptoms as a result of the operation.

Adolescent↗
PubMed1980

Effects of neonatal administration of clomiphene citrate on sexual behavior of female rats: a preliminary report.

Female rats were treated with the nonsteroidal estrogen antagonist clomiphene citrate for the first 5 days postpartum. The expectation was that clomiphene would influence the sexual development of these animals as is the case with sexually immature animals treated with steroidal compounds. Analysis showed that treatment with clomiphene completely disrupted the adult sexual behavior of the female. In five consecutive days of testing the experimental females were never observed to mate. They were mounted significantly less often than controls, suggesting that the males were less attracted to them than to normal females. The initial suggestion that clomiphene might affect the sexual behavior of females has been supported; however, further research must be done to identify the underlying mechanism of the change.

Animals↗
PubMed1980

The effect of alcohol on central auditory processing (comparison with marihuana).

Twelve subjects between the ages of 23 and 62 were tested for changes in hearing acuity and dicrimination after ingestion of four ounces of vodka (80 U.S. proof = 40 per cent ethyl alcohol). As compared with their own pre-alcohol ingestion test results, these subjects revealed, 1) a decrease in discrimination of speech on CID W22 lists under difficult listening conditions, (in quite at 10 dB SL and in noise at a signal-to-noise ratio of -6); and 2) a decrease in performance on a filtered speech test low-pass, high-pass, and binaural fusion. The staggered spondaic word test was moderately affected only in one of the 12 subjects. Pure toe thresholds, speech reception thresholds, and speech discrimination, at 40 dB SL were not influenced. It was concluded that alcohol ingestion in moderate amounts alters the central auditory processing under difficult listening conditions. When compared with a previous study using marihuana, it was found that the discrimination ability was reduced by alcohol ingestion while marihuana significantly improved speech discrimination.

Adult↗
PubMed1979

Layer I of striate cortex of Tupaia glis and Galago senegalensis: projections from thalamus and claustrum revealed by retrograde transport of horseradish peroxidase.

We have examined the origin of the subcortical projections to the superficial layers of the striate cortex in Tupaia glis and Galago senegalensis by using the retrograde transport of HRP. Crystals of HRP were laid directly on the moist pial surface of the cortex which had been gently pricked with a small glass pipette. The diffusion of HRP was limited to layers I and II by restricting the length of time that the HRP was in contact with the surface. Following the application of HRP to the striate cortex, labeled cells were found in restricted regions of the lateral geniculate body of both species. Layers 4 and 5 of galago and layer 3 of tree shrew contained dense clusters of labeled cells. Labeled neurons were also found in the zones between the layers of the lateral geniculate body in both species and these cells were always in register with the labeled cells within the layers. In galago, curved columns of labeled cells were observed in the inferior and superior subdivisions of the pulvinar nucleus. These columns were arranged in the shape of two arcs, joined at the fiber bundle which separates the two subdivisions. The position of the bands in the pulvinar nucleus varied with the locus of the application in the striate cortex. While no labeled cells were seen in the body of the pulvinar nucleus of tree shrew, small labeled neurons were found in the external medullary lamina forming the capsule of the pulvinar nucleus. These cells were continuous with a larger population of labeled cells in the lateral intermediate nucleus. In both species, labeled cells were also found in the intralaminar nuclei (particularly the paracentral nucleus) and in the dorsal-caudal portion of the claustrum. In the claustrum, few unlabeled neurons were present within the zone containing labeled cells. In conclusion, layer I os striate cortex appears to be the site of convergence of several projection systems originating from principal and intralaminar thalamic nuclei as well as the claustrum. The significance of this overlap is discussed in terms of the total cortical extent of each system.

Animals↗
PubMed1979

Thalamic projections to layer I of striate cortex shown by retrograde transport of horseradish peroxidase.

The diffusion of horseradish peroxidase was restricted to layers I and II of the striate cortex in Tupaia glis and Galago senegalensis. In the lateral geniculate body of Tupaia labeled cells were found only in layer 3; some labeled cells were also found in the lateral nucleus. In Galago labeled cells were found only in layers 4 and 5 of the lateral geniculate body; a band of cells was also found in the pulvinar nucleus. These results support the distinction between two overlapping thalamic systems, a layer I and a layer IV system.

Animals↗
PubMed1978

Increased frequency of HLA-DRW4 in chronic active hepatitis.

HLA-A, B, C and DRw typing was performed on peripheral blood lymphocytes of 17 adults with the diagnosis of chronic active hepatitis made by liver biopsy as the only criterion for study. An increase in the frequency of HLA-DRw4 (71 vs. 24%, p less than 0.005) was observed, but there was no increased frequency of HLA-A1, B8 or any other HLA locus specificity.

Adult↗
PubMed1975

I need a friend.

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Child↗