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Biomedical subjects

R Russell

Publications and source records attributed to R Russell.

At least 91 records · Page 5Linked to original sources
PubMed1996

Long term backache after childbirth: prospective search for causative factors.

OBJECTIVES: To assess in a prospective randomised study the association between motor block resulting from high and low dose epidural infusions of bupivacaine in labour and the incidence of long term backache after childbirth, and to compare the incidence of backache in women not receiving epidural analgesia. DESIGN: Women requesting epidural analgesia in labour between October 1991 and March 1994 were randomised to receive infusions of either bupivacaine alone or low dose bupivacaine with opioid. Data were collected during labour and the immediate postpartum period from these women and from women recruited at random over the same time from those who had laboured without epidural analgesia. A postal questionnaire about symptoms was sent three months after childbirth to all women. Further data were collected one year after childbirth from those who had reported new backache at three months. SETTING: St Thomas's Hospital, London. SUBJECTS: 599 women were recruited, of whom 450 (75%) replied to a follow up questionnaire. RESULTS: 152 women (33.8% of responders) reported backache lasting three months after delivery and, of these, 33 (7.3%) had not previously suffered with backache. There were no significant differences between the treatment groups in the incidence of postnatal backache overall or of new backache or any symptoms after childbirth. Among all demographic, obstetric, and epidural variables examined the only factors significantly associated with backache after childbirth were backache before and during pregnancy. CONCLUSIONS: The incidence of new long term backache was not significantly increased in women who received epidural analgesia in labour. Motor block resulting from epidural local anaesthetic administration was not a significant factor in the development of backache.

Adult↗
PubMed1996

Folate synthesized by bacteria in the human upper small intestine is assimilated by the host.

BACKGROUND & AIMS: Some intestinal flora are known to synthesize folate. The aim of this study was to determine whether folate synthesized by small intestinal flora is assimilated by the human host. METHODS: Subjects with atrophic gastritis and healthy volunteers were studied before and after omeprazole administration. A double-lumen perfusion tube was placed in the duodenum. 3H-labeled P-aminobenzoic acid, a precursor substrate for bacterial folate synthesis, was perfused. Downstream intestinal aspirates and a 48-hour urine collection were obtained. RESULTS: Atrophic gastritis and omeprazole administration were associated with increases in duodenal pH and in small intestinal flora. Bacterially synthesized folates were isolated from the intestinal aspirates. Tritiated 5-methyltetrahydrofolate, a major metabolite of folate, was isolated from the urine of omeprazole-treated subjects in greater quantities than from drug-free subjects (P<0.01); the quantity of tritiated 5-methyltetrahydrofolate in the urine of the subjects with atrophic gastritis was similarly elevated. CONCLUSIONS: (1) Mild bacterial overgrowth caused by atrophic gastritis and administration of omeprazole are associated with de novo folate synthesis in the lumen of the small intestine; (2) the human host absorbs and uses some of these folates; and (3) the contribution to folate nutriture from this source remains unclear.

4-Aminobenzoic Acid↗
PubMed1996

Postabsorptive and postprandial energy expenditure and substrate oxidation do not change during the menstrual cycle in young women.

There is little information on the effects of the menstrual cycle on the thermic effect of feeding (TEF) and postprandial substrate oxidation. To address these issues, a dose-response study was conducted in eight young women to whom test meals containing 0, 1046, 2092 and 4148 kJ were administered on nonconsecutive days, once each during the follicular phase and once during the luteal phase of the menstrual cycle. Postprandial energy expenditure was measured until it returned to base line (test duration for the 0 kJ meal was matched to duration of 4184 kJ meal). There was no significant difference between menstrual cycle phases in the duration of the thermogenic response to any size meal. TEF, calculated by four different methods, did not differ between follicular and luteal phases, and a comparable dose-response was observed in both phases. Similarly, there was no effect of menstrual cycle phase on postabsorptive or postprandial protein, fat, or carbohydrate oxidation. In conclusion, postabsorptive and postprandial energy expenditure and substrate oxidations did not differ in young women during the follicular and luteal phases of the menstrual cycle.

Adult↗
PubMed1996

Liver function and morphology after resuscitation from severe hemorrhagic shock with hemoglobin solutions or autologous blood.

OBJECTIVE: To test the effects of three hemoglobin solutions on liver function and hepatic morphology after resuscitation from severe hemorrhagic shock. DESIGN: Prospective study. SETTING: Laboratory. SUBJECTS: Thirty-three beagle dogs. INTERVENTION: Hemorrhagic shock was induced in anesthetized dogs by removal of blood at a rate of 2 mL/kg/min until systolic blood pressure (BP) reached 50 mm Hg. BP was maintained at this level 2 hrs by further withdrawing 5 to 10 mL aliquots whenever BP increased > 50 mm Hg. Resuscitation was then initiated with autologous whole blood (n = 7), 4% pyridoxalated-hemoglobin-polyoxyethylene conjugate (4% PHP [n = 6]), 8% pyridoxalated-hemoglobin-polyoxyethylene conjugate (8% PHP [n = 9], or 8% stroma-free hemoglobin (n = 7). Four dogs were managed identically but were not resuscitated. Gross necropsy and histologic examination of the liver were performed on all dogs after 7 days, or earlier if death occurred. MEASUREMENTS AND MAIN RESULTS: In vitro interferences of PHP and stroma-free hemoglobin with liver function tests were determined and recommendations for interpretation of results from blood samples containing PHP and stroma-free hemoglobin were made. Blood was collected before, during, and after resuscitation from hemorrhagic shock. The dogs were then awakened and survivors were monitored daily with blood sampling until they were killed and necropsy was performed. After 7 days, the survival rate following hemorrhagic shock was 100% for whole blood and 4% PHP, 86% for stroma-free hemoglobin, and 33% for 8% PHP. Of the resuscitated dogs not surviving 7 days, all but one died within 27 hrs from coagulopathy. All dogs not resuscitated died within 1.75 hrs after 2 hrs of shock. Bilirubin, alkaline phosphatase, and lactic dehydrogenase concentrations could not be measured due to interferences of stroma-free hemoglobin and PHP. Aspartate (AST) and alanine (ALT) aminotransferase concentrations could be measured after dilution to overcome the interferences. Significant increases in AST and ALT values in all groups 24 hrs after resuscitation were attributed to hypoxic hepatocellular damage associated with the severity of the shock model rather than to the resuscitation fluid. Liver histology showed no changes attributed to toxic damage of hepatocytes in dogs resuscitated with stroma-free hemoglobin or PHP. However, changes, were less severe in dogs resuscitated with 4% PHP than in other groups. CONCLUSION: Morphologic studies at necropsy and liver function tests in dogs receiving hemoglobin solutions, compared with autologous blood, support the conclusion that the PHP and stroma-free hemoglobin solutions tested did not produce hepatic toxicity when used as resuscitation fluids in this model of severe shock.

Acute Disease↗
PubMed1996

Epidural infusion of low-dose bupivacaine and opioid in labour. Does reducing motor block increase the spontaneous delivery rate?

Labouring women were randomly allocated to receive epidural infusions during labour of either 0.125% plain bupivacaine (n = 200) or a combination of 0.0625% bupivacaine with either 2.5 micrograms.ml-1 fentanyl or 0.25 micrograms.ml-1 sufentanil (n = 199) each starting at 12 ml.h-1 and adjusted as necessary to maintain analgesia. The dose of bupivacaine, both hourly (p < 0.001) and total (p < 0.001), was significantly lower in the group receiving the combination. Motor block was significantly less common and less severe in the combination group (p < 0.001). These reductions did not result in a significant increase in spontaneous deliveries. Maternal satisfaction with first (p < 0.001) and second stage analgesia (p < 0.001) was significantly increased in the combination group. The addition of opioid to the epidural infusion did not reduce the incidence of perineal pain. There were no significant differences between the groups in neonatal outcome or the incidence of early postnatal symptoms.

Adult↗
PubMed1996

Colposcopy in general practice.

Primary care physicians are in an excellent position to identify women most at risk for cancer precursors. They can use a variety of modalities, including colposcopy thus reducing patient anxiety and waiting time. This article describes a training program for such a service, which includes at least 100 colposcopy examinations under supervision. It is applicable outside a hospital clinic setting. Subsequent practice must have a referral base sufficient to maintain competence as well as economic viability. All GP colposcopists in the Perth area attend regular quality assurance meetings. An audit has shown that properly trained GPs can achieve a level of competence equivalent to that expected of their specialist colleagues (89% concordance between colposcopic impression and histology). The format of the audit was based on that of the Royal Australian College of Obstetricians and Gynaecologists (RACOG). Treatment must be performed by experts. General practice is the appropriate location for community screening studies using colposcopy.

Clinical Competence↗
PubMed1996

Bilateral cervicofacial arteriovenous malformations: a case report with unusual complications.

Arteriovenous malformations (AVM) of the craniofacial region are complex problems that require a multidisciplinary approach. Early recognition and proper treatment are essential for an acceptable longterm outcome. This article describes the case of an improperly handled AVM. During the course of retreatment, the left external carotid artery was reanastomosed to gain access for embolization in an attempt to treat the patient definitively. There is also a discussion of classification theories of formation, contemporary treatment, and complications.

Angiography, Digital Subtraction↗
PubMed1995

Toxicity of the novel animal-derived anticancer agent, VRCTC-310: acute and subchronic studies in beagle dogs.

Acute and subchronic toxicities of VRCTC-310, a combination product of crotoxin (CT) and cardiotoxin (CD), which has shown antitumor activity in vivo, have been studied in Beagle dogs. Single i.m. doses of 0.25, 0.5 and 1.0 mg/kg resulted in dose-dependent local muscular toxicity consisting of myofiber atrophy, interstitial edema and macrophage infiltration. Also, AST, ALT and LDH levels increased on day 2, returning to normal values on days 6-8. Local lesions were absent after recovery on day 45. At 2.0 mg/kg, signs of neurotoxicity (ataxia) appeared, in addition to vomitus, salivation, hematuria and myotoxicity in tongue and diaphragm on day 8. Local lesions healed with fibrosis at the site of injection on day 45. Administration of fixed (0.025 and 0.05 mg/kg) or escalating (0.025-0.1 mg/kg) daily doses for 30 days also produced local muscular damage, which was absent at day 75. The increases in AST, ALT and LDH serum activities on days 2-4 were independent of dosing schedule and sharply decreased on day 8, despite continuation of treatment. An escalating dose schedule of 0.025-2.0 mg/kg showed local muscle damage at the site of injection on day 31, however, there were no lesions of myotoxicity in the tongue or diaphragm and no clinical signs of neurotoxicity were observed. Animals tolerated the subchronic treatment better than the acute. The resolution of serum enzymes to normal values during treatment may be attributed to a decrease of sensitivity to VRCTC-310-mediated myotoxic effects.

Animals↗
PubMed1995

Motor block during epidural infusions for nulliparous women in labour: a randomized double-blind study of plain bupivacaine and low dose bupivacaine with fentanyl.

Sixty nulliparous women received epidural infusions in labour of either 0.125% plain bupivacaine or 0.0625% bupivacaine containing 2.5 mcg/ml fentanyl both starting at 12 ml/h and titrated to maintain a sensory block to T10. Those women who received low dose bupivacaine with fentanyl took significantly longer to reach full cervical dilation (P < 0.05). There was no statistical difference between the groups in the number of additional epidural bolus doses required during the infusions. Of the women receiving low dose bupivacaine with fentanyl, 77% required one or no additional top-up doses compared to 87% in the plain bupivacaine group. There was no reduction in the incidence of perineal pain in the group who received fentanyl. Significantly more women who received 0.125% bupivacaine had motor block after 2 h of the infusion (P < 0.05). The mode of delivery was similar in the two groups as was the satisfaction with epidural analgesia in both the first and second stages of labour and with labour overall. There were no significant differences in Apgar scores, umbilical cord blood pH levels or neurologic and adaptive capacity scores at 2 or 24 h. There was no significant difference in the incidence of symptoms 24 h after delivery.

Journal Article↗
PubMed1995

The Christensen prosthesis. A retrospective clinical study.

The objective of this study was to determine if the Christensen temporomandibular joint prosthesis system in an effective alternative in treating patients with severe temporomandibular joint disorders. A total of 69 patients who were not responsive to either nonsurgical or prior surgical treatments were placed into one of three treatment groups depending on the following diagnoses: (1) placement of a glenoid fossa-eminence prosthesis with meniscus retention (22 patients, 40 joints); (2) placement of a glenoid fossa-eminence prosthesis without retention of the meniscus (26 patients, 49 joints); (3) total joint replacement (21 patients, 34 joints). Patients were evaluated immediately before surgery and at regular intervals after surgery for an average of 3.1 years. Success was measured as a significant improvement of function and decrease in pain as measured on a visual analogue scale, as well as improved incisor opening as measured with a Therabite Scale (Lorenz Surgical, Jacksonville, Fla.). Comparison of mean and average pre- and postsurgical values for all groups and criteria showed significant improvement. Results of this study indicate that the Christensen temporomandibular joint prosthesis system may offer a viable method for the treatment of severe temporomandibular joint disease with a high degree of success.

Adult↗
PubMed1995

Shigella enterotoxin 1: an enterotoxin of Shigella flexneri 2a active in rabbit small intestine in vivo and in vitro.

Culture filtrates of Shigella flexneri 2a strain M4243 grown in iron-depleted medium, caused significant fluid accumulation in rabbit ileal loops. Also, when tested in Ussing chambers, a greater rise in potential difference and short circuit current was seen with such filtrates compared with the medium control. Analogous filtrates from two M4243 derivatives lacking the 140-MD invasiveness plasmid (either M4243avir or BS103) retained 60-65% of the wild-type enterotoxic activity. Ultrafiltration and gel exclusion size fractionation of M4243 filtrate revealed that the activity was approximately 60 kD. SDS-PAGE performed on this fraction showed 18 bands, 5 of which reacted with human convalescent sera. Genes encoding this enterotoxin, named ShET1 for Shigella enterotoxin 1, were cloned from the S. flexneri 2a chromosome, and two separate open reading frames of 534 and 186 bp were sequenced. These observations suggest that S. flexneri 2a elaborates two distinct enterotoxins: ShET1, encoded by genes located on the chromosome, and ShET2, encoded by a gene on the 140-MD invasiveness plasmid. ShET1, which is composed of two distinct subunits and is elaborated in vivo, where it elicits an immune response, may be important in the pathogenesis of diarrheal illness due to S. flexneri 2a.

Amino Acid Sequence↗
PubMed1994

Structural similarity between the p17 matrix protein of HIV-1 and interferon-gamma.

The human immunodeficiency virus (HIV) matrix protein, p17, forms the outer shell of the core of the virus, lining the inner surface of the viral membrane. The protein has several key functions. It orchestrates viral assembly via targeting signals that direct the gag precursor polyprotein, p55, to the host cell membrane and it interacts with the transmembrane protein, gp41, to retain the env-encoded proteins in the virus. In addition, p17 contains a nuclear localization signal that directs the preintegration complex to the nucleus of infected cells. This permits the virus to infect productively non-dividing cells, a distinguishing feature of HIV and other lentiviruses. We have determined the solution structure of p17 by nuclear magnetic resonance (NMR) with a root-mean square deviation for the backbone of the well-defined regions of 0.9 A. It consists of four helices connected by short loops and an irregular, mixed beta-sheet which provides a positively charged surface for interaction with the inner layer of the membrane. The helical topology is unusual; the Brookhaven protein database contains only one similar structure, that of the immune modulator interferon-gamma.

Amino Acid Sequence↗
PubMed1994

Studies with cross-linking reagents on the oligomeric form of the paramyxovirus fusion protein.

The oligomeric form of the paramyxovirus simian virus 5 (SV5) fusion (F) glycoprotein has been examined by using chemical cross-linking and sucrose density gradient fractionation. In addition, chemical cross-linking was used to examine the kinetics of assembly of the F oligomer. Analysis by SDS-PAGE on 3.5% gels of the cross-linked F molecules indicated three major species with calculated molecular weights of M(r) approximately 65, M(r) approximately 130, and M(r) approximately 195 kDa, suggesting F monomers, dimers, and trimers, respectively. The cross-linked F species of M(r) approximately 195 kDa migrated on gels faster than influenza virus hemagglutinin trimers and between the dimeric and tetrameric forms of paramyxovirus hemagglutinin-neuraminidase (HN). Furthermore, the F protein oligomer was found to sediment slower than the HN tetramer on sucrose gradient centrifugation. SDS-PAGE analysis of the cross-linked F protein of Newcastle disease virus and human parainfluenza virus 3 showed a pattern very similar to that found for SV5. The data are consistent with those expected for the paramyxovirus F protein being a homotrimer.

Animals↗