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Biomedical subjects

M Moritz

Publications and source records attributed to M Moritz.

At least 37 records · Page 2Linked to original sources
PubMed1995

Three-dimensional structural characterization of centrosomes from early Drosophila embryos.

An understanding of the mechanism and structure of microtubule (MT)-nucleating sites within the pericentriolar material (PCM) of the centrosome has been elusive. This is partly due to the difficulty in obtaining large quantities of centrosomes for analysis, as well as to the problem of attaining interpretable structural data with conventional EM techniques. We describe a protocol for isolating a large quantity of functional centrosomes from early Drosophila embryos. Using automated electron tomography, we have begun a three-dimensional structural characterization of these intact centrosomes with and without regrown MTs. Reconstructions of the centrosomes to approximately 6-8 nm resolution revealed no large structures at the minus ends of MTs, suggesting that if MT-nucleating material physically contacts the MTs, it must conform closely to the shape of the minus end. While many MTs originate near the centrioles, MT minus ends were found throughout the PCM, and even close to its outer boundary. The MTs criss-crossed the PCM, suggesting that nucleating sites are oriented in many different directions. Reconstructions of centrosomes without MTs suggest that there is a reorganization of the PCM upon MT regrowth; moreover, ring-like structures that have a similar diameter as MTs are apparent in the PCM of centrosomes without MTs, and may be MT-nucleating sites.

Animals↗
PubMed1995

Comparative study of results of electronic axiography with results of magnetic resonance imaging including MRI-assisted splint therapy.

The most common temporomandibular joint disturbance is the internal derangement. Its prevalence has been shown to be as high as 28%. The purpose of this study was on one hand to compare the diagnostic efficiency of an electronic axiographic system with magnetic resonance imaging, and, on the other hand to evaluate the results of MRI-assisted treatment monitoring of occlusal splint therapy. The results of this survey clearly show that in evaluation of temporomandibular joint disorders, electronic axiography and magnetic resonance imaging should be used in conjunction with one another to increase the accuracy of positive and differentiated diagnoses. The medical concept of disc recapture involving the use of occlusal splints seems to be merely a clinical term which is not necessarily hinged on anatomical intraarticular changes.

Adult↗
PubMed1995

[Involvement of the trigeminal nerve in fractures of the face].

It is an anatomical particularity of the trigeminal nerve that his three main branches evolve in its peripheral section via a relatively long passage up to an osseous canal. We have tried to provide, apart from a quantitative and qualitative analysis of the lesions of the trigeminal nerve in case of facial fractures, a statement as to their topography in order to enable prognosis as to such lesions. For the study, we used the data of 328 patients with a total of 468 fractures. All patients were asked to provide detailed information about any pre- and postoperative loss of sensibility in the area of the trigeminal nerve. The analysis of the research results allowed indeed for a quantitative statement, not a qualitative one, however. We were able to establish an interrelationship between the topography and a persistent lesion of the nerve for the maxilla and the mandible.

Cranial Nerve Diseases↗
PubMed1994

[Indications for and pertinence of 3D tomodensitometry in panfacial fractures].

Successful treatment of panfacial fractures is dependent on precise clinical and radiological examinations. However, the complexity of fracture lines accounts for the problems and inadequacies of plain films. Three-dimensional CT-reconstruction is recommended to help the maxillofacial surgeon to conceptualize the overall injury. Subsequently, a case involving complex panfacial fractures is presented and the potential value of three-dimensional computed tomography is discussed.

Facial Bones↗
PubMed1994

[Mandibular condyle fractures: conservative treatment versus surgical treatment].

A review of medical literature on the various principles of medical care of condylar fractures confirms that the treatment is still controversial. For a long period of time, the conservative functional treatment of condylar fractures was a dominant philosophy. However, rigid internal fixation of condylar fractures is increasingly accepted as an alternative which presents an improved stability provided by the use of plate and screw fixation techniques. The purpose of this study is to compare the clinical and radiographic long-term results of patients with condylar fractures treated between 1984 and 1992 in our department. 51 patients were treated in a conservative functional way. Rigid internal fixation was performed in 25 patients using an intraoral approach, according to a technique described by Steinhäuser in 1964. The results of this retrospective analysis indicate that in fractures of the condylar head a conservative functional treatment is the therapy of choice. Fractures of the subcondylar region and also--in selected clinical circumstances--fractures of the condylar neck represent indications for a carefully executed rigid internal fixation. The intraoral approach has been proved to cause minimal morbidity and complications.

Adult↗
PubMed1994

Solitary lag screw fixation in the treatment of angle fractures in the mandible: state of the art.

The angle of the mandible forms an area of weakness and is a common site at which fractures occur. This review presents the current state of lag screw fixation of mandibular angle fractures. Treatment philosophies are discussed and the special advantages of this method are mentioned. Despite the positive results of treating angle fractures in the mandible with the solitary lag screw fixation technique, the limitations and complications are clearly pointed out in this article.

Bone Screws↗
PubMed1993

Rejection-independent cholangitis and cirrhosis following orthotopic liver transplantation.

The histologic diagnosis of extrahepatic biliary obstruction in the setting of orthotopic liver transplantation (OLT) may be complicated by nonobstructive factors, such as rejection, preservation injury, drug effects, and infection. Indeed, biopsy specimens from OLT patients frequently exhibit early posttransplant cholestasis, which is likely the result of several of these factors acting in concert. We reviewed the clinicopathologic features of 14 OLT patients whose biopsy specimens displayed prominent cholangitis with "obstructive"-type features. Cholangiograms, Doppler ultrasound examinations, and bacterial cultures were obtained in conjunction with all biopsy specimens. Despite histologic evidence of biliary obstruction, cholangiography revealed obstruction in only one case, leaks in four cases, and nine normal studies. Ten patients had severe systemic bacterial or cytomegalovirus infections. Biliary infection was documented in two cases. Hepatic artery occlusion was diagnosed in one case. The cholangitic pattern persisted in patients with unremitting infections, and two patients developed secondary biliary cirrhosis despite having consistently normal cholangiograms. Features of acute rejection or viral hepatitis were not observed on any biopsy specimen. The presence of this clinicopathologic spectrum was associated with a poor prognosis. Nine patients died and only four patients who responded to antibiotics survived. These findings demonstrate a striking cholangitic response to systemic infections in OLT grafts. The diagnosis of biliary obstruction in OLT liver biopsy specimens cannot be rendered without cholangiographic verification.

Adult↗
PubMed1993

Cadaveric renal transplant in the highly sensitized African-American patient.

A statistically significant difference was discovered when comparing the 1-year graft survival of CAUC and AA. The difference was due in part to nine AA failures that occurred within the first week posttransplant (Fig 3). Using a multivariant analysis both the AA and CAUC were found to be normally distributed in regard to CIT, HLA mismatch, transplant number, and PRA. If these traditional variables thought to have relevance on graft survival in cadaveric renal transplantation are ruled out as contributing factors other avenues must be explored. If credence is given to the theory that the difference in function between AA and CAUC is due to the difference in the number of transplants that failed within the first week then factors such as immunosuppressive therapy and noncompliance can also be ruled out. One possible area of explanation may lie in the area of specificity to HLA antibody. It is possible that these recipients received transplants from a donor to which they were sensitized. A closer analysis of donor and recipient HLA typing as well as the recipient's transfusion and transplant history is recommended. Despite the fact that all transplants occurred in the presence of negative preliminary and final XM's using American Society for Histocompatibility and Immunogenetics (ASHI) certified techniques (Table 2), transplant centers may wish to consider using a more sensitive XM technique such as flow cytometry for these patients. We hope that these recommendations will enable transplant centers to continue their commitment to transplanting the highly sensitized recipient.

Black or African American↗
PubMed1991

Assembly of 60S ribosomal subunits is perturbed in temperature-sensitive yeast mutants defective in ribosomal protein L16.

Temperature-sensitive mutants defective in 60S ribosomal subunit protein L16 of Saccharomyces cerevisiae were isolated through hydroxylamine mutagenesis of the RPL16B gene and plasmid shuffling. Two heat-sensitive and two cold-sensitive isolates were characterized. The growth of the four mutants is inhibited at their restrictive temperatures. However, many of the cells remain viable if returned to their permissive temperatures. All of the mutants are deficient in 60S ribosomal subunits and therefore accumulate translational preinitiation complexes. Three of the mutants exhibit a shortage of mature 25S rRNA, and one accumulates rRNA precursors. The accumulation of rRNA precursors suggests that ribosome assembly may be slowed in this mutant. These phenotypes lead us to propose that mutants containing the rpl16b alleles are defective for 60S subunit assembly rather than function. In the mutant carrying the rpl16b-1 allele, ribosomes initiate translation at the noncanonical codon AUA, at least on the rpl16b-1 mRNA, bringing to light a possible connection between the rate and the fidelity of translation initiation.

Amino Acid Sequence↗
PubMed1991

Elevated intracranial pressure and computed tomography of the brain in fulminant hepatocellular failure.

Cerebral herniation is a leading cause of death in patients with fulminant hepatocellular failure. Classical signs of elevated intracranial pressure are often absent in these patients. A reliable noninvasive method by which the presence of cerebral edema could be determined is much needed. To assess the efficacy of computed tomography of the brain in this setting, we compared the radiographic findings to the intracranial pressure measured by an epidural monitor in patients with fulminant hepatic failure. Unfortunately, a considerable difference existed between the presence of cerebral edema diagnosed by computed tomography of the brain and elevation of the intracranial pressure. Our observations suggest that in patients with fulminant hepatic failure and advanced hepatic encephalopathy, computed tomography of the brain is of little value in detecting cerebral edema. Pressure monitoring is most important to establish the presence and guide the therapy of intracranial hypertension.

Brain↗
PubMed1990

Depletion of yeast ribosomal proteins L16 or rp59 disrupts ribosome assembly.

Two strains of Saccharomyces cerevisiae were constructed that are conditional for synthesis of the 60S ribosomal subunit protein, L16, or the 40S ribosomal subunit protein, rp59. These strains were used to determine the effects of depriving cells of either of these ribosomal proteins on ribosome assembly and on the synthesis and stability of other ribosomal proteins and ribosomal RNAs. Termination of synthesis of either protein leads to diminished accumulation of the subunit into which it normally assembles. Depletion of L16 or rp59 has no effect on synthesis of most other ribosomal proteins or ribosomal RNAs. However, most ribosomal proteins and ribosomal RNAs that are components of the same subunit as L16 or rp59 are rapidly degraded upon depletion of L16 or rp59, presumably resulting from abortive assembly of the subunit. Depletion of L16 has no effect on the stability of most components of the 40S subunit. Conversely, termination of synthesis of rp59 has no effect on the stability of most 60S subunit components. The implications of these findings for control of ribosome assembly and the order of assembly of ribosomal proteins into the ribosome are discussed.

Galactose↗
PubMed1989

Surgical management of severe liver trauma: a role for liver transplantation.

Severe devascularizing liver injuries continue to carry a high mortality. Rapid operative intervention to achieve hemostasis and debride devitalized tissue remains essential to salvaging these patients. For those with unsalvageable liver injuries liver transplantation can be employed. Careful support of the patient in the anhepatic state, reversal of coagulopathy, and use of venous bypass intraoperatively permit successful transplantation.

Adolescent↗