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Biomedical subjects

M Palmer

Publications and source records attributed to M Palmer.

229 records · Page 13Linked to original sources

Sequences homologous to ZFY, a candidate human sex-determining gene, are autosomal in marsupials.

Sexual differentiation in placental mammals results from the action of a testis-determining gene encoded by the Y chromosome. This gene causes the indifferent gonad to develop as a testis, thereby initiating a hormonal cascade which produces a male phenotype. Recently, a candidate for the testis-determining gene (ZFY, Y-borne zinc-finger protein) has been cloned. The ZFY probe detects a male-specific (Y-linked) sequence in DNA from a range of eutherian mammals, as well as an X-linked sequence (ZFX) which maps to the human X chromosome. In marsupials it is also the Y chromosome that seems to determine the fate of the gonad, but not all sexual dimorphisms. Using the ZFY probe we find, surprisingly, that the ZFY homologous sequences are not on either the X or the Y chromosome in marsupials, but map to the autosomes. This implies ZFY is not the primary sex-determining gene in marsupials. Either the genetic pathways of sex determination in marsupials and eutherians differ, or they are identical and ZFY is not the primary signal in human sex determination.

Animals↗

Use of an endoscopic suturing device for laparoscopic resection of the apex of the bladder and umbilical structures in normal neonatal calves.

OBJECTIVE: To develop a laparoscopic technique using an endoscopic suturing device for the resection of the apex of the bladder and the umbilical structures in large-animal neonates. Study Design-Experimental study. Animals or Sample Population-Seven healthy male Holstein calves. METHODS: A laparoscopic technique for resection of the apex of the bladder was developed on 2 calf cadavers, then evaluated on 5 anesthetized calves. The calves were positioned in dorsal recumbency, and 4 ventral abdominal portals were used. The umbilical vessels were double-ligated using an endoscopic suturing device and subsequently transected. The apex of the bladder was transected between a row of laparoscopic clips applied near the apex and atraumatic laparoscopic forceps applied distally; then, the edges were apposed using an endoscopic suturing device. The dissected umbilical remnants were removed from the abdomen through a small incision centered at the umbilicus. One month later, the calves were euthanatized and a second-look laparoscopy performed; then, bladders were collected for gross and histologic examination. RESULTS: No major complications occurred during or after surgery. The endoscopic suturing device permitted both effective ligation of the umbilical vessels and closure of the bladder. During second-look laparoscopy, healing of the peritoneal surface of the bladder and umbilical vessels was assessed to be excellent in 4 calves. A focal adhesion of omentum to the bladder suture line was observed in 1 calf. Focal adhesions of the omentum to the umbilical incision site occurred in 2 calves. The bladder mucosa was completely healed at the surgical sites. CONCLUSION AND CLINICAL RELEVANCE: Resection of the apex of the bladder and umbilical vessels in calves can be accomplished laparoscopically using an endoscopic suturing device.

Animals↗

Promotion of adaptation in battered women: a self-efficacy approach.

The purpose of this article is to describe the use of the Self-Efficacy Scale for Battered Women (SESFBW) in the development of a treatment plan for the abused woman. The authors describe how the SESFBW was developed to assess the self-efficacy needs of women (N = 43) who came to the emergency department with injuries and self-reported current abuse. Four needs related to self-efficacy were identified: a decreased ability to (a) talk to the nurse or doctor about the abusive situation, (b) call a shelter for abused women, (c) shrug off self doubts, and (d) express thoughts and feelings without fear. How data from a self-efficacy assessment were used in developing a teaching plan and intervention is included. Pre- and posttest scores on the SESFBW of six battered women showed a significant increase in self-efficacy scores at the completion of a group educational program. They conclude that the SESFBW is an easy and effective tool to assess self-efficacy and can form the basis for developing an individualized teaching plan to increase self-efficacy.

Adaptation, Psychological↗

Venous gas embolism associated with argon-enhanced coagulation of the liver.

Argon-enhanced coagulation (AEC) is a method for operative coagulation of tissues that utilizes a jet of argon gas encompassing an electrofulguration arc. Concern has been raised that the argon jet may produce harmful venous gas embolization. Two questions were addressed by this study. First, does AEC result in generation of venous gas emboli, and if so, what is the influence of gas flow rate and coagulation power on the amount of gas emboli generated? Second, does the amount of venous gas emboli generated by AEC produce harmful hemodynamic effects? Two AEC units were evaluated during coagulation of cut sections of the liver in pigs. The number of gas emboli generated was measured by an ultrasonic Doppler flow cuff placed around the caudal vena cava. Hemodynamic variables measured following AEC included systemic and pulmonary arterial pressure, pulmonary wedge pressure, and cardiac output by thermodilution. Venous gas emboli were produced during AEC of the liver. The number of gas emboli generated increased with increasing gas flow rates, but was not affected by coagulation power. No change in any of the measured hemodynamic variables was observed following AEC of the liver. The following recommendations were made: (1) Surgeons using AEC should select an argon flow rate as low as feasible to clear a bleeding tissue surface of blood and debris. (2) Although AEC seems to be associated with tolerable amounts of venous gas embolism, surgeons and anesthesiologists should be aware that the potential for harmful venous gas embolism exists. (3) In patients where extensive use of AEC is planned, appropriate monitoring and precautions for gas embolism should be undertaken.

Animals↗

Elevated c-myc messenger RNA in multiple myeloma cell lines.

Oncogene analyses of four human myeloma cell lines provided no indication of gene amplification or rearrangement using DNA probes for the met, raf, abl, mos, erb B, Her-2-neu, fos, myb-7, fms, L-myc, sis, and myb-1 genes. However, a consistent elevation of up to 23-fold in the level of c-myc mRNA was observed in all of the cell lines studied. No restriction fragment length polymorphism (in exons one, two, or three) or c-myc gene amplification has as yet been demonstrated to account for the c-myc mRNA elevation. The c-myc mRNA has a half-life of 25 min which is comparable to that observed in other systems. The elevation in c-myc mRNA is further evidence for the role of the c-myc proto-oncogene in the pathogenesis of myeloma.

DNA Probes↗

Electrophysiological effects of cyclazocine on rat cerebellar Purkinje neurons: comparison with phencyclidine.

Cyclazocine is a benzomorphan which, in addition to more classical opiate properties, binds to the sigma opiate receptor site. Recently, it has been suggested that the sigma opiate receptor is identical to the binding site responsible for the actions of phencyclidine (PCP). Since the electrophysiological actions of PCP have already been demonstrated on rat cerebellar Purkinje neurons, the effects of cyclazocine were also studied in this system with the goal of comparing the electrophysiological effects of cyclazocine to those of PCP. Cyclazocine inhibited the spontaneous firing rates of Purkinje neurons. These responses were stereospecific and qualitatively appeared similar to the effects of PCP. Antipsychotic drugs, haloperidol and fluphenazine, partially antagonized the actions of cyclazocine, suggesting a catecholaminergic involvement similar to the mechanism proposed for PCP. Unlike PCP, the effects of cyclazocine were also partially reversed by the opiate antagonist, naloxone. Taken together, these results suggest that in the rat cerebellum cyclazocine may be interacting with at least two receptor mechanisms: a naloxone-sensitive opiate site, and a naloxone-insensitive site which might involve catecholaminergic mediation similar to the PCP mechanism of action. The naloxone-sensitive effects of cyclazocine, however, may be related to an interaction of the drug with kappa receptors rather than with the more classical mu or delta opiate mechanisms.

Action Potentials↗