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Biomedical subjects

A May

Publications and source records attributed to A May.

At least 199 records · Page 11Linked to original sources
PubMed1994

Red cell dimorphism in a young man with a constitutional chromosomal translocation t(11;22)(p15.5;q11.21).

A constitutional, balanced chromosomal translocation t(11;22)(p15.5;q11.21) was discovered in a tall young man during investigation of a red cell dimorphism. The red cells are predominantly normochromic and normocytic with a small population of hypochromic, microcytic cells. Contained within the regions involved in the translocation are determinants of height (IGF2:11p15.5), red cell haemoglobinization (non-alpha globin gene complex: 11p15.5) and oncogenesis (cHa-Ras-1, Beckwith-Wiedemann syndrome: 11p15.5; BCR, Burkitts lymphoma, Ewings sarcoma: 22q11.21). To map these regions in the patient, somatic cell hybrids were generated and cell lines that segregated the chromosomes 11, 22 and 22q- were obtained. All 11p15.5 sequences investigated, in particular the whole of the non-alpha globin gene complex including its 5' and 3' regulatory sequences, were found to be translocated to 22q-. All chromosome 22 sequences studied were missing from the 22q- cell lines, including the proximal anonymous marker D22S24, and therefore assumed to be translocated to 11p+. These results suggest that the non-alpha globin gene complex has been moved close to the centromeric region of chromosome 22q-. It is postulated that such a positioning subjects the complex to a variegated position-effect bringing about a clonal exclusion of the complex and thus producing a beta-thalassaemia trait mosaic.

Adolescent↗
PubMed1994

Coated and uncoated self-expanding metal stents for malignant stenosis in the upper GI tract: preliminary clinical experiences with Wallstents.

OBJECTIVES: The clinical feasibility of self-expanding metal stents with respect to the technical success, complications, and reintervention rate should be tested. METHODS: Five coated and 26 uncoated prototype Wallstents, especially designed for stenosis of the upper GI tract, were implanted in 23 patients. All patients with dysphagia suffered from inoperable tumor stenosis of the esophagus or the cardia. Stent implantation was performed under slight i.v. sedoanalgesia. RESULTS: Technical success was achieved in all 31 implanted stents. Forty-eight hr after implantation, dysphagia was improved in 21/23 patients. Acute problems observed within 1 wk were stent migration (1 patient, uncoated stent), oblique position of the stent (3 patients), epigastric or retrosternal pain (9 patients), insufficient stent expansion (4 patients), and pouch formation at the upper rim of the stent (4 patients). An uncomplicated follow-up (median 66 days, range 10-139 days) was seen in 12 patients (52%). Major problems in the follow-up period were stent migration in three patients (three coated stents, two stent migrations in one patient) and stent obstruction by tumor ingrowth/overgrowth and/or food impaction in eight patients (35%). Most of these problems could be successfully resolved by implantation of a second stent or electrocoagulation of overgrowing tumor tissue. By the 1st of March, 1994, three patients were still alive with a follow-up period of 530 days (median range, 336-880 days); 20 patients were decreased with a follow-up period of 70 days (median range, 3-374 days). CONCLUSIONS: Implantation of esophageal Wallstents is safe and has a low risk of acute complications and mortality for the patient. Early complications such as perforation and bleeding did not occur. Tumor ingrowth/overgrowth are the major reasons for the high reintervention rate in the follow-up period. Coated stents can resolve this problem, provided that stent migration can be avoided by improvement of the coating technology.

Adenocarcinoma↗
PubMed1994

Hypocomplementaemia of poststreptococcal acute glomerulonephritis is associated with C3 nephritic factor (C3NeF) IgG autoantibody activity.

We have observed that decreased plasma levels of C3 in the serum of three children with poststreptococcal acute glomerulonephritis (PSAGN) at the time of presentation were associated with the presence of C3NeF activity in purified serum IgG from the patients. C3NeF activity was determined using a sensitive assay measuring the ability of patients' IgG to stabilize a preformed cell-bound alternative pathway convertase complex. C3NeF activity of patients' IgG decreased within weeks as plasma levels of C3 progressively returned to normal values. C3NeF activity became undetectable within 1-4 months following normalization of plasma C3 levels. Our observations suggest that early alternative pathway-dependent hypocomplementaemia, a cardinal feature of PSAGN, is mediated by the transient expression of C3NeF autoantibody activity by patients' IgG.

Acute Disease↗
PubMed1994

Piezoelectric shock wave lithotripsy of pancreatic duct stones.

OBJECTIVES: The efficacy of extracorporeal piezoelectric shock wave lithotripsy in patients with obstructing pancreatic duct stones was investigated. METHODS: Fifty patients suffering from chronic pancreatitis and obstructing pancreatolithiasis were treated by ESWL (Piezolith 2500). Shock wave treatment was administered, inasmuch as the stones were not extractable by initially applied endoscopic measures. RESULTS: A total of 119 (2.4 +/- 1.4, range 1-7) lithotripsy sessions were conducted; only mild sedation/analgesia was used. Optimum targeting of the concrements in the shock wave focus was achieved in 17 (14%) treatment sessions with ultrasonography only; it was achieved in 65 (55%) cases by fluoroscopy and, in further 37 (31%) sessions by using both localization systems. Stone fragmentation was successful in 43 (86%) patients. Nineteen (38%) patients achieved spontaneous stone discharge after shock wave lithotripsy. In 11 (22%) cases, it was possible to remove all fragments endoscopically; residual fragments remained in 20 (40%) patients. Severe complications attributable to shock wave application did not occur. During follow-up, six patients had to be referred to surgery; two male patients died of specific diabetic complications and pleural mesothelioma, respectively. Thirty-five (90%) of 39 patients whose conditions were followed for 2-50 (20 +/- 14) months reported improvement of their pain sensations. Six (15%) patients required endoscopic treatment, including ESWL in five of those patients, to be repeated due to recurrent formation of calculi in the main pancreatic duct, which was again successful in five of the six patients. CONCLUSIONS: Piezoelectric shock wave lithotripsy offers a basis for safe and effective fragmentation of pancreatic stones and facilitates endoscopic procedures. Most of the patients with obstructing pancreatic stones became stonefree and showed a significant reduction of pain.

Calculi↗
PubMed1994

[Cerebral angiitis or central side effects after lumbar myelography (with intracerebral vascular spasm)].

This is a case report of severe neurological complications following lumbar radiculography with the non-ionic x-ray contrast agent Iopamidol. The complication, which consisted of serious mnestic disturbances and various neurological deficits including hemiparesis, was due to intracerebral vascular spasms, demonstrated by cerebral angiography, and TCD followed by multiple cerebral infarctions, demonstrated by MRI. A possible causal relationship between the cerebral vascular spasm and intrathecal administration of Iopamidol is discussed.

Cerebral Angiography↗
PubMed1993

Repair of individual DNA strands in the hamster dihydrofolate reductase gene after treatment with ultraviolet light, alkylating agents, and cisplatin.

We have analyzed gene-specific and strand-specific DNA damage and repair in the dihydrofolate reductase gene in hamster cells. Cells were UV-irradiated or treated with two types of chemotherapeutics, alkylating agents or cisplatin. UV-induced pyrimidine dimers were detected using a previously published technique in which the T4 endonuclease V enzyme is used to create nicks at the lesion sites. 6-4 photoproducts were detected in a similar assay using ABC excinuclease after prior reversal of the pyrimidine dimers with photolyase. Adducts formed by the alkylating agents nitrogen mustard and dimethyl sulfate were quantitated by generating strand breaks at basic sites after neutral depurination. Cisplatin-induced intrastrand adducts were detected with ABC excinuclease, and cisplatin interstrand cross-links were detected using a denaturation-reannealing reaction before electrophoresis. In accord with previous reports by other investigators, we find distinct strand specificity of the repair of pyrimidine dimers after UV; the transcribed strand was much more efficiently repaired than the nontranscribed strand. In contrast, there was little or no strand bias in the repair of the 6-4 photoproducts. For alkylating agents, a slight bias toward repair in the transcribed strand was found after treatment with nitrogen mustard, but there appeared to be no bias in the repair after treatment with dimethyl sulfate. Cisplatin interstrand cross-links are repaired with equal efficiency from the two strands, but the more common cisplatin-induced lesion, the intrastrand adduct, is preferentially repaired from the transcribed strand. In conclusion, there is strand bias in the repair of pyrimidine dimers and cisplatin intrastrand adducts, but the strand specificity of repair may not be a general feature for all DNA lesions, as we found little or no strand bias in the repair of other lesions studied.

Alkylating Agents↗
PubMed1993

[The viral and allergic origin of nasal polyposis].

In spite of recent advances in basic science, the etiology and pathogenesis of nasal and paranasal polyps have still not been clarified. Well-defined causal factors are hereditary diseases such as cystic fibrosis and primary ciliary dyskinesia. Allergic and non-allergic processes of the airways, particularly intrinsic asthma and intolerance to non-steroidal antiinflammatory drugs, are implicated in the development of nasal polyposis. In the 1930s nasal polyps were strongly considered to be a manifestation of allergy. The theory was challenged in the 1970s. Many patients with nasal polyps have no identifiable allergic disease. The cause of nasal polyps is speculative. 221 patients were included in this study, 154 suffering from chronic rhinosinusitis and another 46 from nasal polyps. The incidences of aspirin intolerance and of allergy were of no statistic relevance. The data indicate that preoperative cortisone application does improve the disease-free interval.

Aspirin↗
PubMed1993

Repair of ribosomal RNA genes in hamster cells after UV irradiation, or treatment with cisplatin or alkylating agents.

We have measured the DNA damage formation and repair in the ribosomal and the dihydrofolate reductase (DHFR) genes after treatment of hamster cells with different types of DNA damaging agents. In mammalian cells, the ribosomal DNA (rDNA) is transcribed by RNA polymerase I, whereas the DHFR is transcribed by RNA polymerase II, whereas the DHFR is transcribed by RNA polymerase II. Cells were treated with agents that induce different types of lesions, and that are known to be repaired via different pathways. We used UV (254 nm) irradiation, treatment with cisplatin and treatment with the alkylating agents nitrogen mustard (HN2) and methyl methanesulphonate (MMS). UV induced pyrimidine dimers were detected with the enzyme T4 endonuclease V, which creates nicks at the dimer sites; the breaks are then resolved and identified by denaturing electrophoresis and Southern blot. Intrastrand adducts formed by the alkylating agents HN2 and MMS were quantitated by generating strand breaks at abasic sites after neutral depurination. Interstrand crosslinks (ICL) formed by HN2 and cisplatin were detected by a denaturation-reannealing reaction before neutral agarose gel-electrophoresis. We find that the repair of the pyrimidine dimers is significantly less efficient in the RNA polymerase I transcribed rDNA genes than in RNA polymerase II transcribed DHFR gene at 8 and 24 h after irradiation. ICL and intrastrand adducts induced by HN2 are also removed more slowly from the rDNA than from the DHFR gene. In contrast, MMS induced intrastrand adducts and cisplatin induced ICL are repaired equally efficiently in the RNA polymerase I and RNA polymerase II transcribed genes. We conclude that for some types of DNA damage, there is less repair in the ribosomal genes than in the DHFR; but for other DNA lesions there is no difference. The difference in repair efficiency between the rDNA and the DHFR genes may reflect the different RNA polymerase involved in their transcription. It may, however, alternatively, reflect the different nuclear localization of these genes.

Alkylating Agents↗
PubMed1993

Parameters influencing piezoelectric shock wave lithotripsy of biliary calculi.

A total of 225 human gallbladder stones were divided into sets of two, three, or four identical calculi (with maximum diameters of 6-26 mm) and submitted to piezoelectric shock wave lithotripsy in vitro in order to investigate the influence of the following parameters on stone disintegration: shock wave intensity, pulse frequency, and various physicochemical parameters such as the volume and viscosity of the fluid surrounding the stone, the hardness of the calculus, and its chemical composition. The fragmentation efficacy increased with enhanced shock wave energy (P less than 0.01). If the volume of the fluid (30 mL) surrounding the calculus was small, the disintegration end-point (defined by maximum fragment diameters less than or equal to 4 mm) was achieved after a lower number of pulses (median: 250 pulses) than in the case of a large fluid volume (80 mL) (500 pulses; P less than 0.01). On the other hand, however, factors such as the shock wave pulse rate (0.9 Hz vs 1.6 Hz), variations in viscosity of a water-jelly mixture surrounding the stone, the chemical composition of the stones as determined by X-ray diffractometry, and stone hardness were found to have no significant influence on the fragmentation efficacy.

Cholelithiasis↗
PubMed1993

Recurrent gallstone formation after successful extracorporeal shock-wave lithotripsy.

Gallstone recurrence was evaluated in 184 patients exhibiting complete stone disappearance after successful extracorporeal shock-wave lithotripsy (ESWL) and concomitant oral bile acid therapy. Follow-up examinations conducted 6-43 months after termination of adjuvant bile acid therapy revealed recurrent calculi in 40/184 (21.7%) patients (27 females, 13 males, p < 0.01; 13 patients with solitary, 27 patients with multiple stones) after a median stone-free period of 11 months (range 1-33 months; mean +/- SD, 13 +/- 8 months). Therefore, an overall probability of stone recurrence of 11.8% was observed 12 months after complete stone disappearance had been confirmed sonographically and bile salt therapy terminated, and a probability of 25.5% after 24 months. Gallstone reformation occurred in 30/146 (20.5%) patients with initially solitary and 10/38 (26.3%) patients with multiple calculi [not significant (NS)]. Only 3/40 (8%) patients with recurrent calculi reported biliary colic. Sonographic gallbladder contractility values acquired at the time recurrent stones were detected did not show any significant differences, compared with the data obtained in the pretreatment examinations; neither were any differences noted between the patients with gallstone reformation and those who remained stone-free. In 20/33 (61%) patients with recurrent stones who opted for further conservative retreatment (ESWL and/or oral litholysis), complete stone disappearance was achieved a second time. The recurrence rates achieved within the first 3 yr after successful shock-wave lithotripsy of biliary calculi cover a range similar to the rates noted after dissolution therapy.

Adult↗
PubMed1993

[Ergotamine-induced rectal stenosis in a patient with long-term migraine].

A 36 year old woman was admitted to our hospital for treatment of a high-grade rectal stenosis of unknown origin. She had a history of migraine going back 10 years. On intensive questioning she admitted using up to 5 ergotamine-containing suppositories a day. On the basis of history and clinical investigations the rectal stenosis must be connected with the abuse of ergotamine-containing suppositories. This case demonstrates that patients with an unexplained rectal syndrome should be asked for analgetics-containing suppositories specifically. Only discontinuation of treatment in time can preserve the patient from development of a rectal stenosis. In case of a rectal stenosis surgical treatment can be avoided by means of endoscopic controlled dilatation.

Adult↗
PubMed1992

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Health Care Rationing↗
PubMed1992

Use of analgesic agents for invasive medical procedures in pediatric and neonatal intensive care units.

The purpose of this study was to assess the use of analgesic agents for invasive medical procedures in pediatric and neonatal intensive care units. The directors of 38 pediatric units and 31 neonatal units reported that analgesics were infrequently used for intravenous cannulation (10%), suprapubic bladder aspiration (8%), urethral catheterization (2%), or venipuncture (2%). Analgesics were used significantly more regularly in pediatric than in neonatal intensive care units for arterial line placement, bone marrow aspiration, central line placement, chest tube insertion, paracentesis, and lumbar puncture.

Analgesia↗