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Biomedical subjects

R Alexander

Publications and source records attributed to R Alexander.

At least 73 records · Page 4Linked to original sources
PubMed1995

Far lateral disc herniations treated by microscopic fragment excision. Techniques and results.

STUDY DESIGN: This was a retrospective review of a consecutive series of patients who underwent excision of far lateral disc herniations by a paraspinal, muscle-splitting incision that spares the facet. OBJECTIVE: The authors describe the surgical technique in detail and review the results of surgical treatment. SUMMARY OF BACKGROUND DATA: As the lumbar nerve roots exit the intervertebral foramen, they once again lie in juxtaposition to an intervertebral disc and are susceptible to compression with subsequent radiculopathy. Radiculopathy caused by disc herniations in this area is less common, and the anatomy is less familiar to spinal surgeons than that of paramedian disc herniations. The involved root can be approached by a transfacetal approach or by a muscle-splitting approach that spares the facet. METHODS: Thirty-one consecutive patients had undergone the muscle-splitting approach to far-lateral disc herniations. Twenty-five (80.6%) of these patients were available for evaluation at a minimum of 2 years after surgery. Evaluation consisted of history, pain questionnaires, visual analogue scales, physical examination, and plain radiographs. RESULTS: Twelve patients (48%) had excellent results, eight (32%) had good, and five (20%) had either fair or poor results. Low back pain and dysesthesias were causes of unsatisfactory results. No radiographic sign of instability developed postoperatively. CONCLUSION: The anatomy of the nerve root lateral to the pedicle and our technique for microscopic excision of herniated disc fragments lateral to the facet are described. Our overall results were encouraging. The described microscopic technique will hopefully minimize dysesthetic pain that appears to be the result of the manipulation of the dorsal root ganglion.

Adult↗
PubMed1995

Comparison of different methods of administering droperidol in patient-controlled analgesia in the prevention of postoperative nausea and vomiting.

We performed a double-blind, placebo-controlled study to evaluate the different methods of administering droperidol in patients using patient-controlled analgesia (PCA) with morphine. Eighty patients undergoing major orthopedic procedures received temazepam 0.2 mg/kg orally followed by induction of general anesthesia with propofol 2.5 mg/kg, fentanyl 2 micrograms/kg, and vecuronium 0.1 mg/kg. Anesthesia was maintained with nitrous oxide, oxygen, and enflurane. At the end of surgery, all patients received PCA with morphine (0.5 mg/mL, bolus dose 1 mg, and lockout interval 5 min. Before commencement of PCA, patients were randomized to receive droperidol 1.25 mg immediately and, in addition, droperidol 0.16 mg with each PCA dose (Group 1), droperidol 1.25 mg immediately (Group 2), droperidol 0.16 mg with each PCA dose (Group 3), and no droperidol (Group 4). Incidence of nausea and vomiting, request for rescue antiemetics, sedation score, and side effects were recorded every 4 h. Droperidol significantly reduced the incidence of postoperative nausea and vomiting (PONV) (P < 0.01) and request for rescue antiemetic (P < 0.01) compared to placebo. However, there was no difference in the incidence of PONV between droperidol given either as a single dose at the end of surgery (Group 2) or mixed in morphine PCA (Group 3). The addition of droperidol in PCA after an initial dose (Group 1) should be avoided, as it resulted in more sedation and no further reduction in the incidence of PONV compared to Groups 2 and 3.

Adolescent↗
PubMed1995

Comparison of ondansetron and droperidol in reducing postoperative nausea and vomiting associated with patient-controlled analgesia.

In a randomised, placebo-controlled trial we have compared the efficacy of ondansetron and droperidol in reducing postoperative nausea and vomiting associated with patient-controlled analgesia after orthopaedic surgery. One hundred and forty five patients, ASA 1 and 2, undergoing major orthopaedic surgery were anaesthetised using a standardised technique. They were randomly allocated to receive patient-controlled analgesia as morphine 1 mg.ml-1 alone; morphine as before plus a single dose of 1.25 mg droperidol together with 0.083 mg.ml-1 in the infusion syringe; or morphine as before plus 4 mg ondansetron and 0.13 mg.ml-1 in the syringe. The patient-controlled analgesia bolus dose was set at 1 ml with a 5 min lockout and a 4 h maximum dose of 30 mg morphine. There was no background infusion. The occurrence of nausea, vomiting and sedation was assessed every 4 h. The incidence of vomiting decreased from 59% in the morphine-only group to 35% and 14% in the droperidol (p < 0.05) and ondansetron groups (p < 0.001) respectively. The number of patients suffering from nausea alone was not significantly different between the three groups, although those in the ondansetron group experienced less severe nausea (p < 0.05) when using a two point scale. The droperidol group had significantly higher sedation scores than the other two groups (p < 0.005). We conclude that ondansetron is superior to droperidol when used with patient-controlled analgesia and causes less sedation.

Adolescent↗
PubMed1995

Overuse injuries in classical ballet.

Successful management of classical ballet dancers with overuse injuries requires an understanding of the art form, precise knowledge of anatomy and awareness of certain conditions. Turnout is the single most fundamental physical attribute in classical ballet and 'forcing turnout' frequently contributes to overuse injuries. Common presenting conditions arising from the foot and ankle include problems at the first metatarsophalangeal joint, second metatarsal stress fractures, flexor hallucis longus tendinitis and anterior and posterior ankle impingement syndromes. Persistent shin pain in dancers is often due to chronic compartment syndrome, stress fracture of the posteromedial or anterior tibia. Knee pain can arise from patellofemoral syndrome, patellar tendon insertional pathologies, or a combination of both. Hip and back problems are also prevalent in dancers. To speed injury recovery of dancers, it is important for the sports medicine team to cooperate fully. This permits the dancer to benefit from accurate diagnosis, technique correction where necessary, the full range of manual therapies to joint and soft tissue, appropriate strengthening programmes and maintenance of dance fitness during any time out of class with Pilates-based exercises and nutrition advice. Most overuse ballet conditions respond well to a combination of conservative therapies. Those dancers that do require surgical management still depend heavily on ballet-specific rehabilitation for a complete recovery.

Ankle Injuries↗
PubMed1995

Home care challenges for those affected by AIDS.

AIDS is affecting more and more people, yet our health care system has been slow to respond to this growing population. Public interest has focused on AIDS as an acute illness while ignoring the chronically ill, homebound majority of persons with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Enhancing student practicum opportunities: the outbreak investigation option.

An outbreak investigation practicum option for graduate students at the University of Washington School of Public Health and Community Medicine has three goals of education, scientific investigation, and exposure to operations of public health agencies. Over a six-year period, 48 students performed 40 outbreak investigations in collaboration with adjunct faculty based in local public health agencies. An outbreak investigation practicum at Yale University had similar goals, but the rapid-response team approach there generally involved one regular faculty member and a team of graduate students. In either program, the level of faculty involvement necessary for outbreak investigations is sustainable only if the faculty value public health practice as part of the school's mission. Since public health students need to acquire many practical skills, a short outbreak investigation practicum experience should not be viewed in isolation, but rather should be one of a variety of practicum offerings available to students at schools of public health.

Curriculum↗
PubMed1995

Technetium-99m-sestamibi imaging before reoperation for primary hyperparathyroidism.

UNLABELLED: Recent studies have reported high sensitivities for parathyroid localization with 99mTc-sestamibi and have been performed using either 123I/99mTc-sestamibi or a double-phase sestamibi scanning technique. These studies have focused primarily on patients undergoing initial surgery. We studied 35 patients prior to reoperative surgery to investigate the relative sensitivities of these two technique sin this patient population. METHODS: Double-phase sestamibi scanning (early and delayed imaging) was performed in all patients. Evaluable 123I/99mTc-sestamibi subtraction studies were also obtained in 25 patients. Results were correlated with surgical findings in 32 patients and with clinical outcome in 3 patients in whom mediastinal lesions were radiographically ablated. RESULTS: Overall, double-phase sestamibi imaging detected 23 of 39 abnormal parathyroid glands (59%), whereas 123I/99mTc-sestamibi detected 19 of 27 (70%). Oblique imaging, delayed imaging and 123I subtraction all contributed to sensitivity, and 123I subtraction also proved useful in patients with partial thyroid suppression. Two patients had lesions visible on the early sestamibi images that were not seen at all on the delayed scans. There were four false-positive findings. CONCLUSION: No significant differences between double-phase sestamibi and 123I/99mTc-sestamibi subtraction scanning were found, although the latter tended to be more sensitive.

Adenoma↗
PubMed1994

A novel embryo-specific barley cDNA clone encodes a protein with homologies to bacterial glucose and ribitol dehydrogenase.

In order to analyze the genetic programme expressed during the early stages of embryogenesis a cDNA clone bank was constructed from desiccation-tolerant excised barley embryos 18 d after pollination (D. Bartels et al., 1988, Planta 175, 485-492). One of the selected cDNA clones pG31 encodes a transcript of 1300 nucleotides and a protein of 31 kDa, both are specifically expressed in developing embryos and are not detected in other tissues. The expression of the pG31 mRNA is not modulated by the plant hormone cis-abscisic acid but it ceases to be expressed in germinating embryos. The protein sequence deduced from the pG31 transcript shows substantial sequence homologies to bacterial glucose dehydrogenase and ribitol dehydrogenase. Biochemical analysis indicates that glucose dehydrogenase activity is present in protein extracts from embryos 18 d after pollination. This glucose dehydrogenase activity is inhibited by antiserum raised against the recombinant pG31 protein. These findings provide evidence for the discovery of a novel pathway in carbohydrate metabolism acting specifically during embryogenesis.

Amino Acid Sequence↗
PubMed1994

Early identification and treatment necessary to prevent malnutrition in children and adolescents with severe disabilities.

Children with severe developmental disabilities frequently have nutrition and growth problems that range from moderate to severe. Because of notable continuing medical concerns and lowered growth expectations, parents and physicians may fail to recognize gradual deterioration in nutritional status before severe medical complications occur. The two cases reported in this article illustrate the need for early identification and treatment to prevent the development of notable morbidity secondary to malnutrition. Children and adolescents who have growth parameters consistently below age norms require assessment and monitoring by a registered dietitian to detect feeding problems and intake changes and to provide early intervention to help prevent negative consequences (eg, dehydration, protein-energy malnutrition, decubitus ulcers, increased rate and duration of infections, and altered bowel motility). An initial assessment should consist of measurement of length or height, weight, triceps, and subcapsular skinfolds; dietary and feeding history and a review of medical history; and biochemical testing as indicated by the medical and dietary histories. Monitoring frequency, which is determined by age, severity of condition, and response to treatment, may vary from weekly to bimonthly.

Adolescent↗
PubMed1994

Duodenogastroesophageal reflux: relationship to pH and importance in Barrett's esophagus.

BACKGROUND/AIMS: Several reports suggest that duodenogastroesophageal reflux may produce esophagitis, Barrett's esophagus, and esophageal adenocarcinoma. The purpose of this study was to understand better the relationship of pH (< 4 and > 7), duodenogastroesophageal reflux, and fasting bile acid concentrations in producing esophageal damage. METHODS: Using a spectrophotometric technique to measure bile reflux, four groups were studied: healthy subjects, reflux patients, patients with Barrett's esophagus, and patients with esophageal symptoms after partial gastrectomy. RESULTS: Simultaneous 24-hour pH and bile monitoring of distal esophagus found close association between total percent of time pH < 4 and duodenogastroesophageal reflux (r = 0.78; P < 0.001) but a poor relationship (r = -0.06) with total percent of time pH > 7, suggesting that the term alkaline reflux is a misnomer. Duodenogastroesophageal reflux increased significantly with the severity of reflux disease, being greatest in patients with Barrett's esophagus and comparable with that in patients with partial gastrectomy. Fasting bile acid concentrations did not distinguish patients with Barrett's esophagus from those with reflux. Rather, increased quantity of acid reflux was the single factor most characterizing patients with Barrett's esophagus. Omeprazole (20 mg twice daily) normalized acid reflux parameters (13.8% +/- 1.6% to 0.8% +/- 0.6%) and significantly (P < 0.001) decreased duodenogastroesophageal reflux (32.8% +/- 6.9% to 4.7% +/- 1.7%). CONCLUSIONS: Acid reflux is the primary factor in the development of Barrett's esophagus. Bile reflux parallels acid reflux and, at best, may have a synergistic role. Aggressive acid suppression with omeprazole markedly decreases both.

Acids↗
PubMed1994

An accurate method for open reduction and internal fixation of high and low condylar process fractures.

OBJECTIVE: This study was undertaken to evaluate a protocol for open reduction of both high and low condylar fractures that consistently produces accurate reductions, uses rigid internal fixation, and allows immediate function. MATERIALS AND METHODS: This protocol was retrospectively evaluated in 22 consecutive patients (23 fractures). RESULTS: All patients functioned immediately. There were no inaccurate reductions, malocclusions, wound infections, neurosensory deficits, or reports of chronic pain. No patients required reoperation. CONCLUSION: The results of this study indicate that this protocol consistently produces accurate reduction of condylar process fractures and allows immediate function with a minimum of morbidity.

Adolescent↗
PubMed1994

A controlled trial of the effects of esmolol on cardiac function.

We have examined the effects of two different bolus doses of esmolol hydrochloride (Brevibloc) on haemodynamic variables in a placebo-controlled, double-blind, randomized trial. Sixty healthy adult patients undergoing minor orthopaedic surgery were given a standardized general anaesthetic using a laryngeal mask airway. Heart rate (HR), mean arterial pressure (MAP), stroke volume (SV) and cardiac output (Q) were measured (the latter two by Doppler ultrasonography) every 1 min for 5 min after injection of either placebo or esmolol 100 mg or 200 mg. HR, MAP, SV and Q decreased significantly (P < 0.05) for both esmolol groups compared with placebo and, except for MAP, esmolol 200 mg had a greater effect than esmolol 100 mg (P < 0.05). Depression was maximal at 2 min after which recovery was observed but was still incomplete at 5 min.

Adolescent↗
PubMed1994

Evaluation of methods of internal fixation of transverse patella fractures: a biomechanical study.

Biomechanical testing was performed to evaluate five techniques of internal fixation of transverse patella fractures. Using cadaveric lower extremities, transverse osteotomies of the patella were performed, and the simulated fractures were fixed with the following techniques: the modified tension band, anterior tension band with a supplemental cerclage wire (the Pyrford technique), tension band with cancellous bone screws, Pyrford technique with cancellous screws, and cancellous screws alone. The fixation techniques were evaluated by measuring the separation of the fracture fragments during loading to produce a physiologic range of motion (90 degrees flexion to full extension). All techniques functioned adequately, with no fracture gap exceeding 1 mm. The tension band with screws technique performed significantly better than did the modified tension band, with an average fracture gap approximately half that of the traditional modified tension band technique. Mechanically, the addition of the screws to the tension band techniques reduces fracture separation by providing compression throughout the range of motion and by resisting the tensile loading during terminal extension.

Aged↗
PubMed1994

A study of oral morphine preference in inbred mouse strains.

C57BL/6J mice, in two-bottle choice paradigms, show increased oral morphine consumption, compared with DBA/2J mice. To determine whether this C57 morphine preference reflects differences in the receptor-mediated, reward-based action of morphine (as opposed to pharmacokinetic or gustatory differences), three experiments were performed. Consistent with previous two-bottle choice experiments, C57 mean (+/- S.D.) morphine consumption was 18 +/- 3 mg/kg/day, while the DBA mice consumed 1.4 +/- 1.2 mg/kg/day. Intraperitoneal naltrexone produced a 50% decrease in C57 morphine consumption (p < 0.01), while DBA mice showed no change. Consumption of fluid from the control bottle was not changed for either strain. Fifteen and 30 min after oral consumption of a morphine solution, plasma levels of morphine and its glucuronide derivative were not different between these two strains. C57 mice maintained a daily morphine intake of approximately 20 mg/kg across morphine concentrations of 0.05-0.4 mg/ml. These experiments suggest that the difference in oral morphine preference between C57 and DBA mice represents a reward-based mechanism which is mediated through opiate receptors.

Animals↗