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Biomedical subjects

P Maher

Publications and source records attributed to P Maher.

At least 19 recordsLinked to original sources

Copper and calcium binding motifs in the extracellular domains of fibroblast growth factor receptors.

High affinity fibroblast growth factor (FGF) receptors contain a cluster of acidic amino acids in their extracellular domains that is reminiscent of the calcium binding domains of some cell adhesion molecules. Based on this observation, we used a calcium blotting technique to show that FGFR-1 binds calcium and that calcium binding is not observed in a mutagenized form of the receptor that lacks the acidic box region. The acidic box also binds other divalent cations, including copper. This latter interaction appears unique since the binding of copper to FGFR-1 mediates the binding of the receptor to immobilized heparin. While this observation may help explain the angiogenic properties of copper, divalent cation binding to FGF receptors may also mediate the interaction between FGF receptors, cell adhesion molecules and other proteoglycan components of the extracellular matrix.

Animals

Laparoscopic minilaparotomy hysterectomy.

A laparoscopic minilaparotomy hysterectomy technique is described. An abdominal elevator allowed the use of an open 2 cm port in the lower abdomen to introduce the finger and instruments used for laparotomy. The technique was developed in 3 patients with moderate to severe endometriosis. The second and third operations were quicker than could be expected by laparovaginal surgery. The use of laparotomy instruments and techniques make the technique easier to learn, cheaper than techniques using disposable products and has the potential to be faster and possibly safer than current techniques. It retains the advantage of laparoscopy surgery, reduced postoperative pain, small incisions and early discharge from hospital.

Female

Protein kinase C activation inhibits glutamate-induced cytotoxicity in a neuronal cell line.

A neuronal cell line, HT-22, is sensitive to glutamate cytotoxicity via a non-receptor mediated oxidative pathway. 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, blocks this glutamate-induced cell death. Down-regulation of protein kinase C eliminates the protection against glutamate cytotoxicity afforded by TPA. The data suggest that protein kinase C activation blocks an early step in the cytotoxic pathway.

Animals

Laparovaginal hysterectomy.

The technique and complications of 141 patients having laparovaginal hysterectomy in private practice are reported. Abdominal hysterectomy was avoided in the 110 patients having preliminary laparoscopic surgery for pelvic disease, ovarian removal, or a uterus larger than 12cm. Postoperative morbidity included pulmonary embolus (3), vesicovaginal fistula (2) and pelvic haematoma (4). The frequency of complications was less than that reported after abdominal or vaginal hysterectomy. The surgical technique changed during the series; the operative care of the bladder and ureter requires particular attention. A larger number of patients in a variety of centres require study before the laparoscopic procedure can be determined to be as safe as abdominal or vaginal hysterectomy. The laparoscopic procedure has the potential to replace the majority of abdominal hysterectomies.

Evaluation Studies as Topic

Laparoscopic culdotomy.

Laparoscopic culdotomy has been performed in 32 patients. The indications for the procedure included the removal of organs or tissue excised by operative laparoscopy, excision of vaginal endometriosis involving the pouch of Douglas and drainage of a pelvic haematoma. The surgical technique is described and no complications resulted from this technique. Laparoscopic culdotomy has advantages for the removal of lumps exceeding 1 cm, and for the drainage of a pelvic haematoma or pelvic abscess. It is also an integral step in the removal of infiltrating endometriotic lesions in the pouch of Douglas which are attached to the vagina.

Douglas' Pouch

Laparoscopic removal of endometriosis in the pouch of Douglas.

Twenty-six patients with endometriosis in the pouch of Douglas were treated by laparoscopic excisional surgery; previous medical and surgical therapy had failed in 24 of them. Endometriosis in the pouch of Douglas occurred infrequently in association with bladder or ovarian endometriosis. Coital and rectal pain were markedly reduced or cured 6 months after surgery in all except 2 patients. Laparoscopic surgical excision of endometriosis is indicated when drug or other surgical treatments fail and may avoid the need for hysterectomy in some patients.

Adolescent

Biopsy diagnosis and conservative surgical treatment of adenomyosis.

Fifteen patients with dysmenorrhoea and menorrhagia refractory to medical treatment were referred for surgical treatment. Pre-operative diagnosis of adenomyosis was suggested by vaginal ultrasound in 13 patients and was confirmed pre-operatively by myometrial biopsy in 5 and by transcervical myometrial biopsy at the time of endometrial resection in 7. Conservative surgery included endometrial resection (7), myometrial reduction by electrocautery (4), and myometrial excision (3). Marked improvement occurred in 4 of 7 patients after endometrial resection, 3 of 4 after myometrial reduction, and all of 3 having myometrial excision. Diagnosis of adenomyosis is improved by use of vaginal ultrasound and percutaneous or transcervical myometrial biopsy. Conservative surgical procedures including endometrial resection and myometrial reduction or excision may reduce the need for hysterectomy in the presence of adenomyosis.

Adult

Growth factors and vitamin E modify neuronal glutamate toxicity.

The sympathetic nerve cell line PC-12 is killed by glutamate in a concentration-dependent manner. Although glycine and the deletion of magnesium weakly potentiate glutamate toxicity and PC-12 cells express N-methyl-D-aspartate-receptor mRNA, most toxicity is mediated by means of a mechanism independent of typical N-methyl-D-aspartate receptors. Glutamate toxicity is, however, greatly enhanced by prior exposure to nerve growth factor or basic fibroblast growth factor. Glutamate killing is blocked by epidermal growth factor and, to a lesser extent, by vitamin E. These observations show that synergistic interactions between growth factors and excitotoxic amino acids may play critical roles in the developing nervous system and that antioxidants attenuate this toxicity.

Animals

Diagnosis and surgical management of endometriomas.

Fifty two patients with endometriomas greater than 1 cm were treated by surgical excision either with or without ovarian closure. Diagnosis is reliable when clinical features of the pain, vaginal ultrasound, and laparoscopy, including ovarian mobilization and needling, are considered. Fifty of 52 patients were free of pain after 1 year and 26 (50%) became pregnant within 1 year. A second laparoscopy is justified if pain persists or pregnancy does not occur. Adhesive disease was the most common complication (40%), and persistent or recurrent endometriosis occurred in 15%. Surgery by laparoscopy with drainage and excision of the endometrioma without ovarian sutures may be more effective than excision of the endometrioma and ovarian suture.

Endometriosis

Laparoscopic adnexectomy--indications, technique and results.

Laparoscopic adnexectomy was performed successfully in 38 patients in whom the procedure was attempted. Failure may result from inexperience of the surgeon or when preliminary dissection near bowel suggests trauma is likely. The duration of the operation was between 15 and 105 minutes, blood loss was minimal and all but 2 patients were discharged within 24 hours of surgery. Pain was relieved in 33 of 35 patients in whom this was the dominant symptom. In 1 patient a small ovarian remnant implanted on the bladder was removed at subsequent laparoscopy. Preliminary experience of this procedure suggest it may be preferable to laparotomy because of the reduced risk of wound complications, pain, time in hospital and duration of convalescence.

Adolescent

Minimally invasive gynaecological surgery.

Most gynaecological operations can now be performed laparoscopically. The results for patients are a reduction in pain, less time spent in hospital and in convalescence and cost savings. For some procedures the risk of infection and adhesion formation is also reduced. This pelviscopic surgery requires extra training in special surgical skills to overcome the risks that include incomplete surgery resulting from poor access to a pelvic lesion or trauma to organs as a result of poor technique. Most patients with ectopic pregnancy, pelvic adhesions, endometriosis, ovarian cysts and fibromyomata can be treated by this advanced laparoscopic surgery. Hysteroscopic endometrial resection can replace hysterectomy for most patients with menorrhagia who have a normal size uterus.

Female