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Biomedical subjects

K Sharp

Publications and source records attributed to K Sharp.

At least 19 recordsLinked to original sources
PubMed1994

An alternative technique for laparoscopic cholangiography.

The current methods utilized for laparoscopic cholangiography involve cystic duct cannulation and present practical difficulties and potential hazards. An alternative method for intraoperative cholangiography is described which is easy, quick, and safe. The Kumar clamp (a gift from Sabi Kumar, M.D.) is placed across the infundibulum. A 23-gauge sclerotherapy needle is introduced through a side port in the clamp and directed into the infundibulum. The cholangiogram is obtained prior to any dissection in the triangle of Calot, thereby avoiding iatrogenic common bile duct injuries due to misidentification of the cystic duct or anomalous anatomy. To date no pathology has been missed and no complications have resulted from this technique.

Acute Disease↗
PubMed1994

Sociology and the nursing curriculum: a note of caution.

One of the consequences of the expansion of degree, and diploma level Project 2000 courses in nursing, has been that students are now exposed to a significant amount of material from academic disciplines other than nursing, at a relatively advanced level. In this paper, one such discipline, sociology, is considered, and its relevance to the nursing curriculum is assessed. Following a consideration of two theoretical models of the relationship between academic disciplines and professional practice (the 'personal education' and 'semantic conjunction' models), it is argued that whilst the implicit rationale for the inclusion of sociology in the nursing curriculum can best be understood in relation to the latter, neither model offers a convincing reason as to why we should teach sociology to nurses. It is argued instead that the nature of sociological knowledge is inherently multi-paradigmatic, and hence reflexive, and so cannot in principle provide a knowledge base for action-oriented conduct such as nursing work.

Curriculum↗
PubMed1993

On the calculation of pKas in proteins.

This paper describes a general method to calculate the pKas of ionizable groups in proteins. Electrostatic calculations are carried out using the finite difference Poisson-Boltzmann (FDPB) method. A formal treatment of the calculation of pKas within the framework of the FDPB method is presented. The major change with respect to previous work is the specific incorporation of the complete charge distribution of both the neutral and charged forms of each ionizable group into the formalism. This is extremely important for the treatment of salt bridges. A hybrid statistical mechanical/Tanford-Roxby method, which is found to be significantly faster than previous treatments, is also introduced. This simplifies the problem of summing over the large number of possible ionization states for a complex polyion. Applications to BPTI and serine proteases suggest that the calculations can be quite reliable. However, the necessity of including bound waters in the treatment of the Asp-70... His-31 salt bridge in T4 lysozyme and experience with other proteins suggest that additional factors ultimately need to be considered in a comprehensive treatment of pKas in proteins.

Aprotinin↗
PubMed1993

Memory loss during pregnancy.

OBJECTIVE: To investigate possible impairment of memory during pregnancy. DESIGN: The performance of pregnant women in a variety of tests of memory was compared to that of controls. SETTING: The Bristol Maternity Hospital. SUBJECTS: Forty-eight volunteer pregnant women attending for routine antenatal checks were compared to 19 nonpregnant controls. MAIN OUTCOME MEASURES: Subjectively perceived rating of memory impairment, objective measures of recall, recognition and priming memory. RESULTS: Pregnant and control groups were given a series of tests of memory at the end of which they were asked to rate their own memory at present compared to some weeks ago (when they were not pregnant). Of the pregnant women 39 out of 48 (81%) rated their current memory as being impaired; only three out of 19 (16%) of the control subjects did so. Objective tests revealed that the pregnant group was significantly impaired in the recall of lists of words, particularly when learning was incidental rather than explicit. The pregnant group was also significantly impaired in two measures of priming memory. No significant deficit was found in recognition. The deficits were found for both primigravid and multigravid women, and were present in all trimesters of pregnancy. CONCLUSIONS: The majority of women believe their memory to be impaired during pregnancy. Objectively, during pregnancy there is significant impairment of memory as tested by recall or by priming, but not by recognition. The pattern of memory loss differs from that of other amnesic conditions. Information imparted to pregnant patients may not be retained as well as might be expected.

Adult↗
PubMed1993

A review of the results of laparoscopic versus open appendectomy.

Proponents of laparoscopic appendectomy emphasize the advantages of laparoscopic operation--decreased hospitalization, paralytic ileus, postoperative pain and wound complications, including infection. This study compared open laparoscopic appendectomy with laparoscopic appendectomy. To compare the two techniques, patients undergoing laparoscopic appendectomy at four hospitals were compared with patients undergoing open appendectomy during a six month period. Excluded were incidental appendectomies and patients with perforated appendicitis. An equal number of pediatric patients undergoing laparoscopic and open procedures were included in the analysis to avoid bias, because most of the laparoscopic appendectomies were performed in the adult patient population (age of more than 16 years). A University Medical Center, a Veterans Administration and two community hospitals were the settings. Patients undergoing laparoscopic appendectomy (n = 54) had an average age of 25.7 +/- 1.5 (range of six to 59 years). These patients were compared with 121 patients undergoing open appendectomy whose average age was 23.7 +/- 1.8 (range of three to 83 years). The race and gender distribution were similar in the two groups. Traditional open appendectomy was compared with a group of patients undergoing laparoscopic appendectomy. Variables evaluated were operating room time, number of patients who reported nausea, days until patient tolerated a regular diet, days of hospitalization, postoperative pain medication and wound infection rate. Results are expressed as the mean plus or minus standard error of the mean. Analysis of variance was used to compute continuous variables and Fischer's exact test was used for discrete variables. The laparoscopic approach was attempted in 61 patients and completed in 54 patients. Open appendectomy was performed upon 121 patients. Nineteen patients (18 who underwent open operation and one patient who underwent laparoscopic operation) were excluded from further analysis because of perforated appendicitis. The open procedure took less time (p < 0.05). However, there were more wound infections than in the laparoscopic group (seven of 103 versus zero of 53; p = 0.09). Patients with acute appendicitis recuperated more quickly from the laparoscopic procedure, as evidenced by the time until eating regular diet, period of hospitalization, incidence of nausea and pain medications on postoperative day one (p < 0.05). The absence of wound infections after laparoscopic appendectomy can be attributed to the practice of placing the appendix in a sterile bag or into the trocar sleeve before removal from the abdomen. Laparoscopic appendectomy reduces the period of hospitalization, postoperative ileus, nausea and postoperative pain in patients with acute appendicitis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1992

Hypercarbia during carbon dioxide gas insufflation for therapeutic laparoscopy: a note of caution.

During the past decade, the number of laparoscopic procedures performed in the United States, primarily with cholecystectomy, has increased phenomenally. We recently had a patient who developed hypercarbia and cardiovascular compromise during laparoscopic cholecystectomy. The cardiovascular compromise was caused by mechanical factors directly related to increasing intra-abdominal pressures affecting ventilation and venous return as well as the absorption of carbon dioxide (CO2) into the circulation, leading to acidosis and further depression of the cardiopulmonary system. Cardiovascular compromise can be avoided with early recognition of increased end-tidal CO2 concentrations and by preventing intra-abdominal pressures from exceeding 16 mm Hg.

Aged↗
PubMed1990

Voluntary and involuntary maternal separation in guinea pig pups with mothers required to forage.

Lactating guinea pigs required to leave a nest box to obtain food were observed to be separated from their pups almost 10% of the time on Days 13-15 postpartum. The duration of separation was greater in the dark than in the light, and was not different for mothers/litters exposed to low (LFD) versus high (HFD) foraging demand. Subsequently, LFD and HFD pups as well as pups reared under standard laboratory conditions (SLC) all exhibited vocalization and plasma cortisol responses to involuntary maternal separation. However, several effects of rearing were also observed. HFD pups vocalized less during separation and had higher resting cortisol levels than did SLC pups; LFD and HFD males spent less time in contact with the mother in a test cage than did SLC males. These effects are discussed in terms of the importance of the physical environment in shaping infant-mother interactions and the infant's perception of control.

Animals↗
PubMed1989

An analysis of the fourth year of medical school for students pursuing surgical careers.

A fourth-year curriculum survey was forwarded to surgery resident program directors, clerkship directors, and residents. A 37 percent response rate was achieved with comparable representation of each respondent type from 130 institutions. The purpose of the survey was to determine how each of the 3 respondent types rated the importance of 42 subjects or clinical experiences to be taken in the fourth year of medical school for students pursuing surgical careers. The survey also included questions on such issues as externships, early match programs, and guidelines used at their institutions for their fourth year students. The results indicated a significantly high agreement among respondent types on what should comprise surgical students' fourth-year curriculum content. The majority feel the fourth year should be planned by students with an electives advisor to equally add breadth to their general professional education as well as provide prerequisite experiences in the career-chosen discipline.

Clinical Clerkship↗
PubMed1989

Fatal and disastrous complications following percutaneous endoscopic gastrostomy.

Percutaneous endoscopic gastrostomy (PEG) has become the preferred method of nutritional support in virtually every patient in whom this procedure is technically feasible because of its apparent technical facility, cost containment, and bedside insertion. PEG can, however, be associated with serious complications and death. This is a report of three patients who developed life-threatening abdominal wall abscesses and four patients who died after PEG insertion. The patients ranged in age from 30 to 80 years, four female and three male. Complicating medical conditions included cirrhosis, diabetes, heart-lung transplantation, neurological dysfunction, and psychosis. The four patients who died were all noted to have had unsatisfactory adhesion between the gastric serosa and the anterior abdominal wall, resulting in large gastric defects where the PEG had been placed and intraperitoneal contamination with gastric contents and feedings. Three additional patients developed abdominal wall abscesses requiring operative debridement. The patient considered to be high risk for surgical gastrostomy may be a higher risk for PEG. Alternatives to PEG should be considered in patients with poor nutritional status or debilitating medical conditions, or in patients undergoing immunosuppressive therapy and steroid use. Psychosis and dementia should be considered relative contraindications to PEG because these patients may dislodge the gastrostomy tube, resulting in severe wound infection and, possibly, death.

Adult↗
PubMed1987

Computer simulations of the diffusion of a substrate to an active site of an enzyme.

Computer simulations of the diffusion of a substrate to an enzyme active site were performed. They included the detailed shape of the protein and an accurate description of its electrostatic potential. Application of the method to the diffusion of the superoxide anion to the protein superoxide dismutase revealed that the electric field of the enzyme enhances the association rate of the anion by a factor of 30 or more. Calculated changes in the association rate as a function of ionic strength and amino acid modification paralleled the observed behavior. Design principles of superoxide dismutase are considered with respect to insights provided by the simulations. A possible means of enhancing the enzyme turnover rate through site-directed mutagenesis is proposed.

Binding Sites↗
PubMed1986

Focusing of electric fields in the active site of Cu-Zn superoxide dismutase: effects of ionic strength and amino-acid modification.

In this paper we report the implementation of a finite-difference algorithm which solves the linearized Poisson-Boltzmann equation for molecules of arbitrary shape and charge distribution and which includes the screening effects of electrolytes. The microcoding of the algorithm on an ST-100 array processor allows us to obtain electrostatic potential maps in and around a protein, including the effects of ionic strength, in about 30 minutes. We have applied the algorithm to a dimer of the protein Cu-Zn superoxide dismutase (SOD) and compared our results to those obtained from uniform dielectric models based on coulombic potentials. We find that both the shape of the protein-solvent boundary and the ionic strength of the solvent have a profound effect on the potentials in the solvent. For the case of SOD, the cluster of positive charge at the bottom of the active site channel produces a strongly enhanced positive potential due to the focusing of field lines in the channel-a result that cannot be obtained with any uniform dielectric model. The remainder of the protein is surrounded by a weak negative potential. The electrostatic potential of the enzyme seems designed to provide a large cross-sectional area for productive collisions. Based on the ionic strength dependence of the size of the positive potential region emanating from the active site and the repulsive negative potential barrier surrounding the protein, we are able to suggest an explanation for the ionic strength dependence of the activity of the native and chemically modified forms of the enzyme.

Amino Acids↗