Biomedical subjects

A Mammen

Publications and source records attributed to A Mammen.

11 recordsLinked to original sources

PubMed2001

Nipple aspirate cytology and pathologic parameters predict residual cancer and nodal involvement after excisional breast biopsy.

We previously demonstrated that abnormal nipple aspirate fluid (NAF) cytology predicted residual breast cancer (RC) and tumour size after excisional biopsy (EB), although normal NAF cytology did not exclude RC. Tumour size correlates with the risk of lymph node (LN) metastases. LN metastases provide prognostic information allowing medical and radiation oncologists to determine the need for adjuvant therapy. We hypothesized that pathologic factors known after EB, combined with NAF cytology, would predict with a high degree of accuracy the presence of RC and LN spread. NAF cytology and pathologic parameters: tumour distance from biopsy margins, multifocal and multicentric disease, sub-type of ductal carcinoma in situ (DCIS) or invasive cancer (IC), grade of DCIS or IC, tumour and specimen size, tumour and biopsy cavity location, presence or absence of extensive DCIS, and biopsy scar distance from the nipple were evaluated bivariately and then by logistic regression (LR) for their association with RC and involved LN (> or = 1 (+) LN, useful to determine chemotherapy need, and > or = 4 (+) LN, useful to determine radiation need to the chest and axilla). Data were analysed using NAF cytology alone, pathologic parameters alone, and NAF cytology and pathologic parameters combined. The combined LR model was superior in predicting residual cancer (94%) to LR models using NAF cytology (36%) or pathologic parameters (75%) alone. When only subjects with normal NAF cytology were evaluated by LR, the model was 92% sensitive in predicting RC. Tumour size and NAF cytology predicted which patients had > or = 1 (+) LN, whereas tumour and specimen size predicted which patients had > or = 4 (+) LN. We propose an algorithm which, if confirmed in a larger study, may allow clinicians to be more selective in their recommendations of re-excision breast biopsy or mastectomy.

Adult↗

PubMed1997

[Change in corneal sensitivity after topical dorzolamide administration. A comparative study].

BACKGROUND: The new antiglaucoma drug, dorzolamide, mainly evokes local side effects like eye burning, pruritus, blurred sight and a foreign-body sensation. A clinical study was conducted to determine it dorzolamide has any influence on corneal sensitivity. SUBJECTS AND METHODS: We examined three different groups of substances. We used sodium chloride solution 0.9% and the local anesthetic oxybuprocaine 0.4% as control groups, each in two subgroups aged 23-40 years or 60-86 years. Corneal sensitivity was measured in the corneal center with Draeger's electronic optic aesthesiometer. We took the measurements directly before and 1,5,10,15 and 20 min after applying one eye drop. RESULTS: The control groups with sodium chloride solution showed no significant (P > 0.05) corneal hyposensitivity. The local anesthetic caused corneal asensitivity (P < 0.05) until the 10-min measurement. Twenty minutes after giving the anesthetic, with 12.10(-5) N corneal sensitivity nearly reached the starting value. At this time corneal sensitivity in the older subgroup was still decreased with 627.10(-5) N. In the younger subgroup dorzolamide only caused slight, but significant (P < 0.05), hyposensitivity of the cornea 1 and 5 min after application of the eye drop. CONCLUSION: Although dorzolamide decreases corneal sensitivity only a little, people with glaucoma using contact lenses should not insert them until at least 15 min after applying the dorzolamide.

Adult↗

PubMed1997

Rare pancreatic tumours in children (other than nesidioblastosis).

BACKGROUND: The rarity of pancreatic tumours other than nesidioblastosis in children is such that the experience of any one surgeon or institution is small. As a consequence, there is limited information on the appropriate management and outcome of these tumours. For this reason a review was conducted of the experience of a large paediatric surgical institution. METHODS: During a 23-year period, six patients with pancreatic tumours other than nesidioblastosis were treated at the Royal Children's Hospital, Melbourne. RESULTS: Despite the varied modes of presentation and surgery undertaken, all six patients with surgery alone, with follow-up from 1 to 18 years. Two of the tumours were malignant; the remaining four being islet cell adenomata. No form of adjuvant treatment (chemotherapy or radiotherapy) was used. CONCLUSION: These rare paediatric tumours appear to have a good prognosis, even when malignant, and respond well to radical surgical ablation. Adjuvant therapy appears to be unnecessary.

Adenoma, Islet Cell↗

PubMed1996

Interaction of the N-methyl-D-aspartate receptor complex with a novel synapse-associated protein, SAP102.

Ionotropic glutamate receptors are known to cluster at high concentration on the postsynaptic membrane of excitatory synapses, but the mechanism by which this occurs is poorly understood. Studies on the neuromuscular junction and central inhibitory synapses suggest that clustering of neurotransmitter receptors requires its interaction with a cytoplasmic protein. Recently, in vitro studies have shown that members of the N-methyl--aspartate (NMDA) class of glutamate receptors interact with a synapse-associated protein, SAP90 (PSD-95). However, evidence for the in vivo interaction of NMDA receptors with SAPs is still lacking. In the present study, we demonstrate the specific interaction between SAP102, a novel synapse-associated protein, and the NMDA receptor complex from the rat cortical synaptic plasma membranes using co-immunoprecipitation techniques. No association was observed between SAP102 and GluR1, a member of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate class of glutamate receptors. To identify the domain on the NMDA receptor responsible for this interaction, we constructed hexahistidine fusion proteins from different regions of the NR1a and NR2 subunits of the NMDA receptor. Immunoblot overlay experiments showed that while the C-terminal domain of the NR2 subunit displayed strong binding, the NR1a intracellular C-terminal tail did not interact with SAP102. The site of interaction was more precisely located to the last 20 amino acids of the NR2 subunit as indicated by the interaction of the synthetic peptide with SAP102. In summary, we demonstrate here for the first time an in vivo interaction between the native NMDA receptor complex and a synapse-associated protein. These results suggest that SAP102 may play an important role in NMDA receptor clustering and immobilization at excitatory synapses.

Animals↗

PubMed1993

Neurotransmitter release regulated by nitric oxide in PC-12 cells and brain synaptosomes.

BACKGROUND: Nitric oxide is a messenger molecule of the nervous system, which is produced by the enzyme nitric oxide synthase, which may regulate cyclic guanosine monophosphate levels and which has been implicated in the control of neurotransmitter release. PC-12 pheochromocytoma cells differentiate to form neuronal cells in culture when they are exposed to nerve growth factor. The levels of cyclic guanosine monophosphate in the cells and their ability to release acetylcholine in response to K(+)-depolarization are both maximal after eight days of treatment with nerve growth factor. We set out to assess a possible role for nitric oxide in the processes that occur in differentiating PC-12 cells. RESULTS: Nitric oxide synthase is first evident in differentiating PC-12 cells eight days after beginning treatment with nerve growth factor, coinciding with the marked increase in K(+)-depolarization-induced release of acetylcholine. The release of both acetylcholine and dopamine in response to K(+)-depolarization is blocked by inhibitors of nitric oxide synthase and by hemoglobin, which binds nitric oxide. Providing l-arginine, a precursor required for nitric oxide synthesis, reverses the effects of the inhibitors. In synaptosomal preparations from the corpus striatum, inhibitors of nitric oxide synthase prevent the release of glutamate in response to the glutamate derivative N-methyl-d-aspartate but not in response to K(+)-depolarization. CONCLUSION: Nitric oxide may mediate the release of acetylcholine and dopamine in response to K(+)-depolarization in PC-12 cells and the release of glutamate in response to N-methyl-d-aspartate in striatal synaptosomes. Nitric oxide synthase expression is induced after eight days of treating PC-12 cells with nerve growth factor, coinciding with a marked enhancement of the release of neurotransmitters in response to K(+)-depolarization.

Journal Article↗

PubMed1990