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Biomedical subjects

H Martin

Publications and source records attributed to H Martin.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Outcome of combined trabeculectomy with cataract operation and intraocular lens implantation].

BACKGROUND: When trabeculectomy and cataract extraction with intraocular lens insertion are combined, do the success and complication rates add. MATERIAL AND METHODS: Follow-up of 47 eyes of 34 patients with combined trabeculectomy and cataract extraction with intraocular lens implantation after 12 to 42 months. RESULTS: With a low perioperative complication rate the intraocular pressure after one year was below 22 mm Hg in 90% without any medication and in 98% additional glaucoma therapy. After 2 and 3 years the intraocular pressure was normal without any additional therapy in 83% of the eyes. The visual acuity was better or equal to the preoperative value in 89% of the cases. CONCLUSIONS: The combination of trabeculectomy and of cataract extraction with intraocular lens implantation has a low complication rate and gives good results regarding intraocular pressure and visual rehabilitation. When a trabeculectomy is indicated, the indication for a simultaneous cataract extraction with intraocular lens implantation should not be to restricted.

Aged↗
PubMed1998

Use of somatostatin receptor scintigraphy to image extrahepatic metastases of neuroendocrine tumors.

BACKGROUND: The presence of lymph node metastases significantly influences the modality of treatment in patients with liver metastases of neuroendocrine tumors (NET). Somatostatin receptor scintigraphy (Octreo-Scan, Mallinckrodt-Diagnostica, Petten, the Netherlands) is a method for localization and staging NET. The aim of our prospective study was to evaluate the effectiveness of somatostatin receptor scintigraphy in the identification of extrahepatic tumor spread. METHODS: Thirty-five patients with liver metastases of NET were studied over a 5-year period. The presence of NET was confirmed histologically in all cases. To detect extrahepatic metastases or local tumor recurrence, conventional imaging techniques and somatostatin receptor scintigraphy were carried out. RESULTS: In correlation with the findings of conventional imaging methods, somatostatin receptor scintigraphy confirmed liver metastases in all patients. Additionally, 19 of 35 patients (54.2%) had extrahepatic tumor lesions not detected by other imaging techniques. Of those, 15 had extensive abdominal or thoracic lymph node metastases, 3 patients had bone metastases, and in 1 patient with bronchial carcinoid local tumor recurrence was detected. All 19 patients were excluded from further evaluation for liver resection or transplantation and subjected to conservative treatment. The somatostatin receptor scintigraphy sensitivity, confirmed at the time of operation, was 91.6%. In 1 patient, in whom cluster transplantation was performed, somatostatin receptor scintigraphy failed to disclose disseminated carcinosis of the pleural cavity, detected at autopsy (false-negative rate 8.3%). CONCLUSION: In our experience, somatostatin receptor scintigraphy provides a highly sensitive diagnostic method to localize metastases of NET. We recommend somatostatin receptor scintigraphy before liver surgery in every patient with hepatic metastases of NET to identify candidates suitable for resection.

Bone Neoplasms↗
PubMed1998

[Incidence of endomycoses in the autopsy material of the Berlin Charité Hospital].

From 1970 to 1993, a total of 93 endomf1p4es confirmed by post-mortem examination was diagnosed in the autopsy material of the Berlin Charité, a large hospital with an average of 1,500 hospital beds and maximum medical care. These comprised 51 candidoses (54.8%), 24 aspergilloses (36.6%), five cryptococcoses (5.4%), one zygomycosis, 1 trichosporosis and one coccidioidomycoses. This corresponded to 0.7% of the 13,375 decreased persons autopsied during this period. The frequency of autopsy was 85.3%. In 3,770 cases (2,418 adults and 1,352 children), brain dissection was performed. An adequate clinical putative diagnosis was made in only six out of 28 patients (18 adults, 10 children) with histologically confirmed cerebral mycosis [11 candidoses (39.3%), 10 aspergilloses (35.7%), five cryptococcoses (17.9%), one trichosporosis and one coccidioidomycosis]. About 80% of the mycoses of the CNS thus remained undetected while the patients were alive. Against the background of the continuing reduction in the frequency of autopsy in the Federal Republic of Germany, the observations made in the present paper underscore the demand for improved efficiency of mycological in-vivo diagnoses in the hospital and laboratory.

Adult↗
PubMed1998

Evidence for a novel MAPKKK-independent pathway controlling the stress activated Sty1/Spc1 MAP kinase in fission yeast.

The fission yeast Sty1/Spc1 MAP kinase, like the mammalian JNK/SAPK and p38/CSBP1 kinases, is activated by a range of environmental insults including osmotic stress, hydrogen peroxide, heat shock, UV light and the protein synthesis inhibitor anisomycin. Sty1 is activated by a single MAPKK, Wis1. We demonstrate that the conserved MAPKKK phosphorylation sites Ser 469 and Thr 473 in the catalytic domain of Wis1 are normally essential for Sty1 activation. However, when mildly overexpressed, a mutant Wis1 kinase lacking these conserved phosphorylation sites is able to support stress inducible gene expression and activation of the Sty1 MAP kinase in response to an oxidative or osmotic stress or to a mild heat shock. We show that phosphorylation and activation of Sty1 under these conditions is not due to inactivation of the Pyp1 MAP kinase phosphatase. These results reveal a novel MAPKKK-independent pathway by which the Wis1 MAPKK can activate the Sty1 MAPK in response to stress in fission yeast.

Amino Acid Sequence↗
PubMed1998

Noninvasive assessment of stiffness and failure load of human vertebrae from CT-data.

A calculational method based on noninvasively derived data for the assessment of the mechanical quality of individual vertebrae is presented. Dimensional data obtained from serial, segmented CT scans were used as the geometric input for a newly developed finite element model designed to calculate stiffness and failure load of these complex bone structures. Mechanical, structural data for cancellous bone was obtained by measurements of the compressive strength and failure load of actual vertebral specimens obtained at autopsy. The stiffness and failure load calculated by the newly developed finite element model were compared with the data obtained from mechanical measurements of vertebral specimens. A high correlation between measured and calculated failure load was found (r = 0.89, p < 0.001, n = 16). The correlation between the failure load and bone mineral density (BMD) was significant (r = 0.82, p < 0.001, n = 16). A similar correlation between calculated and measured stiffness (r = 0.81, p < 0.001, n = 15) was also found using the finite element model described herein. Thus the newly developed calculation methodology has been verified and can be used to predict the failure load and stiffness of osteoporotic vertebrae using data obtained non-invasively from CT scans.

Adult↗
PubMed1997

Cytomegalovirus monitoring by polymerase chain reaction of whole blood samples from patients undergoing autologous bone marrow or peripheral blood progenitor cell transplantation.

Sensitive screening for cytomegalovirus (CMV) by polymerase chain reaction (PCR) following autologous bone marrow or peripheral blood progenitor cell transplantation has not been evaluated. In a three-center study, 98 autograft transplant recipients were prospectively screened for CMV infection by PCR and culture techniques. At a median of 20 days (range, 3-28) after transplantation, 21 (39.6%) of 53 CMV-seronegative patients were PCR positive for CMV, and at a median of 17 days (range, 7-84) after transplantation, 19 (42.2%) of 45 CMV-seropositive patients were PCR positive for CMV. Low-level DNAemia (1-10 fg CMV DNA/mL blood) occurred for 1 week in 31 patients but was never associated with CMV disease. Of 9 patients who presented with at least two consecutive positive PCR results, 1 developed CMV pneumonia. No patients died because of CMV disease. Screening for CMV infection by PCR had a negative predictive value of 100% (as also observed after allogeneic transplantation), but its positive predictive value was significantly lower.

Adolescent↗
PubMed1997

Intrathecal sufentanil, fentanyl, or placebo added to bupivacaine for cesarean section.

UNLABELLED: We compared the effects of intrathecal sufentanil 2.5 and 5 microg, fentanyl 10 microg, and placebo when administered together with hyperbaric bupivacaine 0.5% 12.5 mg for cesarean section. The study was performed in a randomized, double-blind fashion in 80 (20 per group) healthy, full-term parturients presenting for elective cesarean section. Postoperative pain was assessed using the visual analog scale (VAS). Duration of complete analgesia was defined as the time from the intrathecal injection to VAS score > 0. Duration of effective analgesia was defined as the time to VAS score > or = 4. No patient experienced intraoperative pain. Complete analgesia was prolonged in all groups receiving opioids. Effective analgesia was prolonged and the 0- to 6-h intravenous opioid requirements were lower in the groups receiving sufentanil compared with those receiving fentanyl and placebo. The need for intraoperative antiemetic medication was greater in the placebo group. Pruritus was a frequent and dose-related side effect in the groups receiving sufentanil. There were no differences in umbilical cord blood gases or neonatal Apgar scores and neurological and adaptive capacity scores among the groups. In conclusion, the addition of sufentanil or fentanyl improved the quality of subarachnoid block compared with placebo. The duration of action was longer for sufentanil than fentanyl. IMPLICATIONS: Small doses of fentanyl or sufentanil (synthetic opioids) added to bupivacaine (local anesthetic) for spinal anesthesia for cesarean section reduce the need for intraoperative antiemetic medication and increase the duration of analgesia in the early postoperative period compared with placebo.

Adult↗
PubMed1997

Complications of central venous access devices in children with and without cancer.

OBJECTIVE: Complications of indwelling central venous access devices (CVAD) were assessed in 63 children with cancer and 35 without cancer. METHODOLOGY: Central venous access devices placed surgically in 1991 were reviewed for complications. RESULTS: In cancer patients, the median CVAD duration was 211 days (range 9-924), compared to 37 days (range 3-339) in the non-cancer patients. Although significantly more CVAD, 41 of 72 (57%), were infected in the cancer patients compared to 14 of 40 (35%) CVAD in the non-cancer patients (OR = 2.46, 95% CI 1.03-5.93), the rate of line infection in cancer patients was lower: 2.8 per 1000 catheter days compared with 7.6 per 1000 in non-cancer patients (P = 0.0014). Infection was significantly more common in intensive chemotherapy cancer patients (P = 0.0002). CONCLUSIONS: Treating infected CVAD with antibiotics or hydrochloric acid (HCl), clearing occluded lines with streptokinase/HCl and repairing fractured lines, when successful, resulted in a considerable gain in the number of days of use for the CVAD.

Adolescent↗
PubMed1997

Skin microcirculation before and after local warming in infants delivered vaginally or by caesarean section.

To elucidate early postnatal changes in skin microcirculation, term newborn infants were studied at 2, 6 and 24 h after vaginal delivery (VD, n = 20) or elective caesarean section (CS, n = 10). Laser Doppler technique was used to measure perfusion, rhythmical perfusion changes, i.e. vasomotion, and reactive hyperaemia of the dorsal hand, before and after local warming of the skin to 37 degrees C. The skin perfusion and the magnitude of reactive hyperaemia (mean 85%) remained essentially unchanged, while vasomotion increased from 0-5 to 2-8 cycles/min (p < 0.001) during the first day of life. Local warming of the skin promoted microcirculation slightly at 2 h and more markedly at 24 h postnatal age. The CS group showed a higher degree of skin perfusion, vasomotion and reactive hyperaemia than did VD infants at 2 h postnatal age. Our findings most likely reflect skin microcirculatory effects of birth-related events, such as a drop in body temperature, sympathoadrenal activation and placental transfusion.

Blood Pressure↗
PubMed1997

Plasma cAMP: a hepatorenal link influencing proximal reabsorption and renal hemodynamics?

The existence of a hepatorenal link is suggested by several pathophysiological observations (indirect actions of glucagon on the kidney, hepatorenal syndrome), but the nature of this link remains unidentified. We propose that extracellular circulating cyclic AMP could be this link. Cyclic AMP (cAMP) is the intracellular second messenger of glucagon (G) action in the liver, and this organ is known to release cAMP in the blood in relatively large amounts after G administration. On the other hand, the proximal tubule (mainly the pars recta) is known to take up cAMP through the organic acid transport system. We observed that the glucagon-induced rise in phosphate excretion, which requires supraphysiologic concentration of G, was significantly correlated with the simultaneous rise in plasma cAMP and could be mimiked by i.v. infusion of cAMP alone. Moreover, we showed that a significant hyperfiltration (similar to that induced by supraphysiologic G) can be observed if cAMP (mimicking G-induced hepatic release) is coinfused with a much lower, physiologic, amount of G. Taken together, these observations suggest that: (1) cAMP is a hepatorenal link and that plasma cAMP permanently influences the intensity of reabsorption in the pars recta of the proximal tubule; and (2) that cAMP participates, in conjunction with G, to control GFR. Insulin is known to exert an inhibitory influence on G-induced cAMP release by the liver and will thus weaken the indirect (cAMP-mediated) influence of G on renal function. This "pancreato-hepatorenal cascade" may explain the natriuretic effects of G and antinatriuretic effects of insulin, and probably contributes to disturbances observed in some pathophysiological situations such as the edema of liver cirrhosis or hyperfiltration of diabetes.

Absorption↗
PubMed1996

Pharmacological characterization of CCKB receptors in human brain: no evidence for receptor heterogeneity.

In this paper, cholecystokinin (CCK) B-type binding sites were characterized with receptor binding studies in different human brain regions (various parts of cerebral cortex, basal ganglia, hippocampus, thalamus, cerebellar cortex) collected from 22 human postmortem brains. With the exception of the thalamus, where no specific CCK binding sites were found, a pharmacological characterization demonstrated a single class of high affinity CCK sites in all brain areas investigated. Receptor densities ranged from 0.5 fmol/mg protein (hippocampus) to 8.4 fmol/mg protein (nucleus caudatus). These CCK binding sites displayed a typical CCKA binding profile as shown in competition studies by using different CCK-related compounds and non peptide CCK antagonists discriminating between CCKA and CCKB sites. The rank order of agonist or antagonist potency in inhibiting specific sulphated [propionyl-3H]cholecystokinin octapeptide binding was similar and highly correlated for the brain regions investigated as demonstrated by a computer-assisted analysis. Therefore it is concluded that CCKB binding sites in human cerebral cortex, basal ganglia, cerebellar cortex share identical ligand binding characteristics.

Adult↗
PubMed1996

Identification of 14-3-3 proteins in human platelets: effects of synthetic peptides on protein kinase C activation.

The 14-3-3 proteins inhibit protein kinase C (PKC) activity in vitro and contain conserved sequences that resemble the pseudosubstrate domain of PKC and the C-terminus of the annexins. In the present study we have identified the isoforms of 14-3-3 in human platelets and used synthetic peptides derived from the regions with similarity to PKC and annexins to examine the potential role of 14-3-3 in regulating platelet activity. Immunoblotting studies with isoform-specific antisera raised against the acetylated peptides corresponding to the N-termini of 14-3-3 showed that these cells express high levels of the beta, gamma and zeta 14-3-3 isoforms. In addition, low levels of the epsilon and eta 14-3-3 isoforms were detected. In washed, saponin-permeabilized platelets incubated with [gamma-32P]ATP, thrombin- and phorbol 12-myristate 13-acetate (PMA)-induced phosphorylation of several proteins (66, 45, and 20kDa) was inhibited by preincubation with AS peptide (KNVVGARRSSWRVISSIEQK) based on the pseudosubstrate-like region of the 14-3-3 family. A control peptide of similar size had no effect on PKC-mediated phosphorylation. PMA caused a rapid translocation of PKC activity from the cytosol to the particulate fraction of saponin-permeabilized platelets that was unaffected by either the AS peptide or a peptide derived from the annexin-like 14-3-3 domain (MKGDYYRYLAEVATGDD). These results suggest that isoforms of the 14-3-3 family may play an important physiological role as inhibitors of PKC activity in human platelets but are unlikely to be involved in controlling association of PKC with the membrane.

14-3-3 Proteins↗
PubMed1996

The loss of stiffness as osteoporosis progresses.

The routine diagnosis of osteoporosis is based on radiological measurements of bone mineral content. An osteoporotic failure is influenced both by a loss of mineralized bone and internal bone structure. The structure cannot be estimated by bone reconstruction based on standard radiological equipment. To investigate the influence of structure on cancellous bone stiffness, a new finite element model of cancellous bone is developed. The model describes a cancellous bone unit as an open-celled structure. Trabecular length, trabecular thickness, diameter of trabecular connections, relative lattice disorder and relative bone loss determine the real architecture. Using this model, the loss of stiffness as a result of trabecular thinning and loss of trabecular connections is estimated. The volume fraction as a scalar value for a volume can not be a marker for orthotropic stiffness changes. A formula in the form Y = e(a *1 n(X) + b) can describe the correlation between cancellous bone stiffness and volume fraction. These formulas are appropriate for those cases, when the loss of bone mineral (decrease in trabecular thickness) is closely connected to a loss of structure (increasingly perforated trabecular network).

Bone Density↗