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Biomedical subjects

A Forster

Publications and source records attributed to A Forster.

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

The effects of solution concentration and epinephrine on lateral distribution of hyperbaric tetracaine spinal anesthesia.

In a search of a differential spinal block between dependent and nondependent sides, we investigated whether the use of a larger concentration of hyperbaric tetracaine (T) and/or the omission of epinephrine (E) would provide differential spread in patients left for 15 min in the lateral decubitus position. Spinal anesthesia was performed in the lateral decubitus position with the operated side dependent in 60 patients scheduled for lower limb surgery. All patients remained lateral for 15 min after spinal injection before being turned supine. They received 12 mg of T in 10% dextrose and E 0.2 mg was added when predicted duration of surgery was more than 90 min. The concentration of T to be used for each patient was randomized. This resulted in four groups of 15 patients: T 0.5% + E (control group), T 1% + E, T 0.5%, and T 1%. A unilateral anesthesia was defined as the presence of an adequate sensory (L-1 or higher) and/or motor (3 degrees) blockade on the dependent side and the absence of one or both modalities on the nondependent side, or as a duration of sensory (regression to L-2) and motor (1 degrees of recovery) blockade 20% longer on the dependent compared to the nondependent side. None of the 60 patients showed unilateral sensory block. A comparable number of patients in all groups showed unilateral motor block: four in T 0.5% + E, two in T 1% + E, four in T 0.5%, and five in T 1%. Likewise, a comparable number of patients in all groups showed a prolonged duration of sensory and motor block, respectively: six and eight in T 0.5% + E, six and nine in T 1% + E, six and eight in T 0.5%, and seven and seven in T 1%. In conclusion, although a preferential distribution of hyperbaric T toward the dependent side in patients of all four groups was noticed, the use of a larger concentration of T, omission of E, or combination of these two factors did not provide a more marked differential spread when compared to the standard solution of T 0.5% + E.

Adrenergic Agonists↗
PubMed1996

Long term evaluation of septic arthritis in hemophilic patients.

Before 1983, septic arthritis was rare in patients with hemophilia. With the advent of human immunodeficiency virus infection in the hemophilia population, many centers noted an increasing incidence of patients with septic arthritis. Fifteen septic joints in 10 patients with severe hemophilia were documented. Eight patients were human immunodeficiency virus positive, 1 was human immunodeficiency virus negative, and 1 was not tested. The diagnosis was delayed in 5 patients because the symptoms are similar to an acute hemarthrosis. An elevated temperature was common. The white blood cell count was elevated in only 1/3 of the infections, being modified by human immunodeficiency virus infection. Associated risk factors included infected angioaccess catheters (2), pneumonia (2), and generalized sepsis (1). All but 1 joint responded to appropriate antibiotics and either repeated aspiration or arthrotomy. However, 6 patients died of acquired immunodeficiency syndrome from 2 to 109 months after infection. Three patients are alive 29, 86, and 96 months, respectively, after infection.

Adolescent↗
PubMed1996

Hemiplegic shoulder pain (HSP): natural history and investigation of associated features.

The prevalence of hemiplegic shoulder pain (HSP) and associated factors was studied in patients with a stroke followed for 6 months after discharge from hospital. A questionnaire was used to evaluate shoulder symptoms and an examination of the shoulder and arm was carried out three times over 6 months. A total of 108 patients were studied with a mean age of 71 years. Sixty-nine patients (63.8%) developed HSP at some time during the study period. The number with HSP was 39 at discharge from hospital, 59 at 8 weeks post-discharge and 36 at 6 months. Nine carers reported lifting the patient by pulling on the hemiplegic arm, even though six of them had received advice about correct lifting techniques. Reduced shoulder shrug was associated with HSP at all times and reduced pinch grip was also associated with HSP at discharge from hospital. Patients who required help with transfers were more likely to suffer with HSP. There was no difference in the prevalence of HSP in patients treated at the day hospital compared to those who received domiciliary physiotherapy. It is concluded that HSP is common after a stroke and the prevalence increases in the first weeks after discharge from hospital. Stroke patients and their carers need advice about correct handling of the hemiplegic arm, and more work is required to ensure that correct handling occurs after discharge in patients at high risk of this unpleasant complication.

Activities of Daily Living↗
PubMed1995

Association of erythroid transcription factors: complexes involving the LIM protein RBTN2 and the zinc-finger protein GATA1.

The RBTN2 LIM-domain protein, originally identified as an oncogenic protein in human T-cell leukemia, is essential for erythropoiesis. A possible role for RBTN2 in transcription during erythropoiesis has been investigated. Direct interaction of the RBTN2 protein was observed in vivo and in vitro with the GATA1 or -2 zinc-finger transcription factors, as well as with the basic helix-loop-helix protein TAL1. By using mammalian two-hybrid analysis, complexes involving RBTN2, TAL1, and GATA1, together with E47, the basic helix-loop-helix heterodimerization partner of TAL1, could be demonstrated. Thus, a molecular link exists between three proteins crucial for erythropoiesis, and the data suggest that variations in amounts of complexes involving RBTN2, TAL1, and GATA1 could be important for erythroid differentiation.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Incidence and consequences of falls due to stroke: a systematic inquiry.

OBJECTIVE: To undertake a systematic inquiry into the incidence and consequences of falls in a cohort of elderly patients with stroke after discharge from hospital. DESIGN: Administration of a questionnaire to patients and main carers at discharge from hospital and eight weeks and six months later. SETTING: Bradford Metropolitan District. SUBJECTS: 108 patients recruited to the Bradford community stroke trial. Patients were recruited to the trial if they were 60 years or over and resident at home with some residual disability. MAIN OUTCOME MEASURES: Number of falls, motor club assessment, Barthel index, Frenchay activities index, and Nottingham health profile. Stress in carers was indicated by the general health questionnaire. RESULTS: Of 108 patients, 79 (73%) fell in the six months after discharge from hospital with a total of 270 falls reported. Patients who fell in hospital were significantly more likely to fall at least twice at home after discharge (chi 2 = 8.16; P = 0.004). "Fallers" (two or more falls) were less socially active at six months and more had depressed mood. Carers of these patients were significantly more stressed at six months (53% v 18%; chi 2 = 8.5; P = 0.003). CONCLUSION: Stroke is associated with a risk of falling at home and affects the lives of patients with stroke and their carers. Falling and fear of falling is an important issue which needs to be dealt with by the multidisciplinary team.

Accidental Falls↗
PubMed1995

The Na(+)-translocating ATPase of Acetobacterium woodii is a F1F0-type enzyme as deduced from the primary structure of its beta, gamma and epsilon subunits.

A 4.5 kbp EcoRI fragment hybridizing to a fragment of uncD (coding for subunit beta of F1F0-ATPases) was cloned from chromosomal DNA of Acetobacterium woodii. The nucleotide sequence was determined and revealed five open reading frames (ORF), four of which were identified to code for subunits of the Na(+)-ATPase. The deduced amino acid sequences of these ORF's are homologous to subunit alpha (partial coding sequence, C-terminal end), gamma, beta and epsilon of F1F0-ATPases from various organisms; furthermore, the organization of the genes in the order uncA (alpha), uncG (gamma), uncD (beta), uncC (epsilon) is identical to the structure of unc operon as present in most bacteria. Downstream of uncC is an ORF whose deduced amino acid sequence has 53% sequence homology to AlgD from Pseudomonas aeruginosa. The structure and organization of the unc genes are the final proof that the Na(+)-ATPase from A. woodii is a member of the family of F1F0-ATPases.

Acetobacter↗
PubMed1995

Characterization of haemorrhages at the origin of the sternocleidomastoid muscles in hanging.

Haemorrhages at the periostal-clavicular origin of the sternocleidomastoid muscles were found in 52 out of 54 cases of death by hanging. This cervical haemorrhage is most frequently found in death by hanging, but only seldomly seen in other causes of death and can therefore be regarded as being typical for death by hanging. The frequency of this finding on the side of the highest point of the ligature mark is significantly higher, thereby supporting the hypothesis of extension as the causative mechanism. External cardiac massage and assisted breathing have no influence on the occurrence of haemorrhages. Histology shows the haemorrhages to be mainly directly epiperiostal, however, many cases displayed concurrent sub- and intraperiostal extravasations. Artificial post mortem production of these findings is discussed in the light of the literature.

Adolescent↗
PubMed1995

Laparoscopic extraperitoneal inguinal hernia repair complicated by subcutaneous emphysema.

The case of a healthy 59-yr-old man who underwent elective laparoscopic extraperitoneal inguinal hernia repair and general anaesthesia is presented. After one hour of surgery, a sudden increase in the FETCO2 from 5.0% to 9.4% in relation to a massive subcutaneous emphysema, but without any haemodynamic instability, was noticed. The acute rise of FETCO2 was the first sign of an abnormal event. Nevertheless, subcutaneous emphysema was diagnosed with chest wall examination and palpation. Subcutaneous emphysema and hypercarbia are potential complications of laparoscopic surgery, but are more likely to occur in extraperitoneal surgery, since insufflated CO2 can diffuse easily into the surrounding tissues. High insufflation pressures will increase chances of this occurring and was the most likely cause of this complication. This case encouraged us to make recommendations for the management of laparoscopic extraperitoneal surgery which included: monitoring of CO2 insufflation pressure, routine examination and palpation of chest wall, use of N2O with caution, adjusting ventilation to physiological FETCO2 and excluding other causes of subcutaneous emphysema and hypercarbia.

Hernia, Inguinal↗
PubMed1995

Hospital- and home-based rehabilitation after discharge from hospital for stroke patients: analysis of two trials.

We examined the methodology and results of two previously published randomized controlled trials of home- and hospital-based rehabilitation for stroke patients after discharge from hospital in Bradford and Nottingham, in view of apparently discrepant findings in the two trials. In an analysis of the combined findings of both studies, there was little difference in terms of efficacy between home- and hospital-based care, but a small advantage in favour of home therapy was found in reducing disability between hospital discharge and 6 months. Contrary to an earlier report, we did not find a differential effect of treatment between those who were and those who were not frail. We conclude that home therapy is the method of stroke after-care of choice in urban settings in the UK, although this conclusion may not apply in other health-care settings and further studies are required.

Activities of Daily Living↗
PubMed1995

Quantitative evaluation of tourniquet leak during i.v. regional anaesthesia of the upper and lower limbs in human volunteers.

Although it is accepted that during i.v. regional anaesthesia (IVRA) local anaesthetic can leak under the tourniquet into the systemic circulation, no published study has evaluated this leak quantitatively. In volunteers, during two random sessions, we have simulated IVRA using standard techniques with a radiolabelled compound which is chemically similar to lignocaine and has comparable tissue distribution (0.1 mg of HIDA labelled with 100 muCi of 99mTc in 40 ml of saline). The decrease in radioactivity was measured with a gamma camera for the 20 min of tourniquet inflation and for the 20 min of washout after cuff deflation. While the tourniquet was inflated, the leak for the lower limb (mean 29 (SD 8) %) was significantly greater (P < 0.004) than the leak for the upper limb (15 (5) %). Moreover, in each of 10 volunteers, the leak was always greater for the lower than the upper limb. During the first 3 min after tourniquet deflation the loss of radioactivity was 58 (8) % of the maximal amount for the upper limb and 39 (8) % for the lower limb (P < 0.001). As the leak under the tourniquet was significantly greater for the lower than the upper limb, we conclude that IVRA for the lower limb can be associated more frequently with a shorter duration of successful anaesthesia and/or failure.

Adult↗
PubMed1995

A prospective study of the feasibility of continuous spinal anesthesia in a university hospital.

A prospective study was undertaken in an elderly population undergoing orthopedic surgery to specifically study the feasibility of continuous spinal anesthesia (CSA). In a university hospital, 14 residents and 5 junior staff, using an 18-gauge needle and a 20-gauge catheter, performed 76 and 24 consecutive CSAs, respectively. There was an overall failure rate of 6%, all occurring in the residents' group. The causes affecting the success of CSA were inability to identify the subarachnoid space in 5/6 cases (all lumbar punctures were performed using the midline approach) and, in one case, inability to thread the catheter. The six failed CSAs were ultimately performed successfully by one of the senior authors. All surgeries were successfully performed with CSA, without requiring general anesthesia or intravenous narcotic supplementation. Anesthesia was initiated with isobaric bupivacaine in 94/100 cases. In 18% of patients, inadequate anesthesia prompted modifications of the local anesthetic solutions (i.e., type, baricity, total dosage) before surgery. One case of minor neurologic complication was observed, but no postspinal headache occurred. In conclusion, our findings led us to pursue CSA with large-bore equipment in an elderly population; furthermore, we believe that teaching the earlier use of alternative approaches other than the midline approach could further reduce our failure rate.

Aged↗
PubMed1995

Prevalence and associated features of the cold hemiplegic arm.

BACKGROUND AND PURPOSE: Some stroke patients complain of an unpleasant sensation of coldness in the hemiplegic arm. This study aimed to determine the prevalence of this symptom and any associated features. METHODS: A questionnaire about symptoms in the arms was sent to patients at least 12 months after stroke. Reflex sympathetic dystrophy (RSD) was diagnosed if four typical symptoms were present in the arm. RESULTS: One hundred patients were recruited and 75 complete replies received. The mean age of the patients was 74 years, and the mean time since the stroke was 19 months. Forty patients (53%) experienced unilateral coldness in the hemiplegic arm. In 14 this sensation was constant, and 10 rated the symptom as troublesome. The symptom developed at a median time of 1 month after stroke, but only 13 patients (32%) sought advice from a doctor. Sensory symptoms and arm and shoulder pain were common, but the only symptoms associated with coldness were numbness (P < .001) and color change (P < .05). Fifteen patients fulfilled the diagnostic criteria for RSD, 13 of whom had coldness only in the hemiplegic arm. CONCLUSIONS: A sensation of coldness in the hemiplegic arm is common and distressing. It is associated with numbness and color changes in the arm. Some cases are caused by RSD, but other patients have coldness that may be due to other causes such as a vasomotor abnormality.

Aged↗
PubMed1994

Specific in vivo association between the bHLH and LIM proteins implicated in human T cell leukemia.

The protein products of proto-oncogenes implicated in T cell acute lymphoblastic leukemia include two distinct families of presumptive transcription factors. RBTN1 and RBTN2 encode highly related proteins that possess cysteine-rich LIM motifs. TAL1, TAL2 and LYL1 encode a unique subgroup of basic helix-loop-helix (bHLH) proteins that share exceptional homology in their bHLH sequences. We have found that RBTN1 and RBTN2 have the ability to interact with each of the leukemogenic bHLH proteins (TAL1, TAL2 and LYL1). These interactions occur in vivo and appear to be mediated by sequences within the LIM and bHLH domains. The LIM-bHLH interactions are highly specific in that RBTN1 and RBTN2 will associate with TAL1, TAL2 and LYL1, but not with other bHLH proteins, including E12, E47, Id1, NHLH1, AP4, MAX, MYC and MyoD1. Moreover, RBTN1 and RBTN2 can interact with TAL1 polypeptides that exist in assembled bHLH heterodimers (e.g. TAL1-E47), suggesting that the RBTN proteins can influence the functional properties of TAL1. Finally, we have identified a subset of leukemia patients that harbor tumor-specific rearrangements of both their RBTN2 and TAL1 genes. Thus, the activated alleles of these genes may promote leukemia cooperatively, perhaps as a result of bHLH-LIM interactions between their protein products.

Amino Acid Sequence↗
PubMed1994

The LIM protein RBTN2 and the basic helix-loop-helix protein TAL1 are present in a complex in erythroid cells.

Chromosomal translocations in T-cell acute leukemias can activate genes encoding putative transcription factors such as the LIM proteins RBTN1 and RBTN2 and the DNA-binding basic helix-loop-helix transcription factor TAL1 associated with T-cell acute lymphocytic leukemia. While not expressed in normal T cells, RBTN2 and TAL1 are coexpressed in erythroid cells and are both important for erythroid differentiation. We demonstrate, using anti-RBTN2 and anti-TAL1 antisera, that the LIM protein RBTN2 is not phosphorylated and is complexed with the TAL1 phosphoprotein in the nucleus of erythroid cells. A complex containing both RBTN1 and TAL1 also occurs in a T-cell acute leukemia cell line. Since both RBTN2 and TAL1 are crucial for normal erythropoiesis, these data have important implications for transcription networks therein. Further, since both proteins can be involved in leukemogenesis, these data provide a direct link between proteins activated by chromosomal translocations in T-cell acute leukemia.

Adaptor Proteins, Signal Transducing↗
PubMed1994

Glucuronidation and isomerization of all-trans- and 13-cis-retinoic acid by liver microsomes of phenobarbital- or 3-methylcholanthrene-treated rats.

Glucuronidation and isomerization of all-trans-retinoic acid (tr-RA) and 13-cis-retinoic acid (13-cis-RA) were investigated in an in vitro system using liver microsomes of differently pretreated rats. In agreement with their thermodynamic stability, more retinoic acid was isomerized from the 13-cis form to the all-trans form than vice versa. Also some 9-cis-retinoic acid (9-cis-RA) could be found. Isomerization was reduced, but in contrast to glucuronidation was still important if boiled microsomes were used. This supports the view that isomerization can proceed as a non-enzymatic process. 3-Methylcholanthrene (MC) pretreatment of the rats increased the microsomal glucuronidation of 13-cis-RA and tr-RA and the formation of 13-cis-retinoyl-beta-glucuronide was enhanced up to 7-fold by MC-induced rat microsomes. The rates of glucuronidation by uninduced and phenobarbital-induced rat microsomes differed only slightly. In addition to glucuronides of the applied retinoic acid isomers (13-cis-RA and tr-RA), 9-cis-RA and its glucuronide were found. Induction of retinoid glucuronidation by pretreatment with MC indicates that this metabolic reaction is catalysed by a MC-inducible UGT isozyme. After two recently described pathways (conversions of retinol to retinal and of retinyl methyl ether to retinol) this is a third step of retinoid metabolism, induced by pretreatment with MC. With human microsomes no more than traces of glucuronides were detected; also, incubations with human microsomes resulted in a lower degree of isomerization than with rat microsomal fractions.

Animals↗
PubMed1994

Cysteine-rich LIM domains of LIM-homeodomain and LIM-only proteins contain zinc but not iron.

The structure of LIM domains has major implications for transcription because proteins such as Is1-1 contain two LIM domains associated with a homeodomain, and RBTN1/Ttg-1 and RBTN2/Ttg-2 contain two LIM domains but no homeodomain. Conserved cysteine and histidine residues in the LIM domains suggest a metal-binding role. RBTN and Is1-1 LIM proteins have been made in Escherichia coli and insect cell expression systems and their metal content has been determined using atomic absorption spectroscopy and electron paramagnetic resonance spectroscopy. LIM proteins expressed in soluble form contain zinc atoms, whereas bacterial inclusion bodies invariably also have Fe-S clusters. The latter are identified as linear [Fe3S4]+ clusters and appear to result from incorrect metal coordination by E. coli. These studies show that RBTN1, RBTN2, and Is1-1 are metalloproteins that contain zinc but not iron and, therefore, that the LIM domain represents a zinc-binding domain.

Cysteine↗
PubMed1994

Intrathecal midazolam reduces isoflurane MAC and increases the apnoeic threshold in rats.

The purpose of this study was to examine the anaesthetic requirement of intrathecal midazolam in a dose-response fashion in isoflurane-anaesthetized, tracheostomized rats, and to evaluate the apnoeic threshold after each intrathecal midazolam dose. Intrathecal midazolam, 5, 10, 20, and 30 micrograms, was administered to 25 anaesthetized tracheotomized rats. Isoflurane MAC was determined by the tail-clamp method. The effect of intrathecal midazolam on the apnoeic threshold was evaluated, and light and electron microscopy studies were performed on cervical, thoracic and lumbar sections of the spinal cord to investigate possible midazolam-induced neurotoxic effects. Intrathecal midazolam 5, 10, 20 and 30 micrograms decreased isoflurane MAC by 16%, 31%, 42%, and 53% respectively (P < 0.05). The apnoeic threshold was increased by midazolam 5 micrograms (from a PaCO2 of 4.25 +/- 0.55 to 5.28 +/- 0.76 kPa, P < 0.05) when compared with baseline values, but not further by additional doses. Light and electron microscopy studies on sections taken from the spinal cord of four animals did not show any morphological changes suggestive of midazolam-induced neurotoxicity when compared with similar preparations obtained from controls. These data suggest that intrathecal midazolam possesses dose-dependent antinociceptive properties which, associated with the ceiling effect of the apnoeic threshold obtained at the lowest midazolam dose and the lack of neurotoxic effects, may potentiate inhalational anaesthesia without producing marked respiratory depression.

Anesthesia, Spinal↗