Biomedical subjects
Publications and source records attributed to R Maurer.
The case is reported of a 64-year-old man in whom a pedunculated tumor of the Vallecula epiglottica occurred and was excised. Histologically it proved to be a dedifferentiated liposarcoma. The patient is well and free of disease 18 months later. The literature is reviewed and 20 other cases of liposarcoma in the laryngeal region are discussed.
Massive bilateral adrenal hemorrhages are a rare complication of anticoagulant therapy. Among over 34,000 autopsies of adults we found six patients with such hemorrhages. Two were women and four men with a mean age of 81 years. They had been hospitalized and anticoagulated for various reasons. The hemorrhage occurred within ten days of anticoagulation, was always bilateral and massive and destroyed the adrenal cortex, thus leading to acute adreno-cortical insufficiency. The diagnosis in all patients was made only at autopsy. Main symptoms are abdominal pain, progressive hypotension, electrolyte disorders and disturbances of consciousness. In patient on anticoagulant therapy, these symptoms justify the suspicion of adrenal hemorrhage and the institution of lifesaving substitution therapy. Pathogenetically these hemorrhages are attributed to the combined effects of stress-induced adrenocortical tissue damage and increased bleeding tendency. The findings in our patients are compared with those of 83 patients from the literature.
Myelolipomas are rare, benign, usually asymptomatic tumors of the adrenals consisting of fatty and hemopoietic tissue. New imaging techniques lead increasingly to incidental findings. Diagnosis of a myelolipoma is confirmed by fine needle aspiration yielding mature adipose tissue together with hematopoietic cells, in particular megakaryocytes. Pathophysiology is unclear, correlations to hormonal disturbances are discussed and increased incidence of hypertension associated with myelolipoma has been reported. We describe a female patient who was found at evaluation of hypertension to have a myelolipoma of more than 1 kg of weight. Liposarcoma was suspected and the tumor excised. After excision blood pressure returned to normal.
Eighty-three previously untreated patients with aggressive non-Hodgkin's lymphomas were treated with either MACOP-B (23 patients) or VACOP-B (60 patients) as originally described by Klimo and Conners [1, 2]. Their median age was 46 years. Thirty-seven patients had stage I or II and 46 stage III or IV disease. The tumor histopathology was reviewed in all cases. Sixty-five patients had intermediate grade and 18 high-grade non-Hodgkin's lymphomas according to the International Working Formulation. The rate of complete response was 74% for MACOP-B and 76% for VACOP-B. At the time of analysis the duration of follow-up was 50 months for the MACOP-B and 22 months for the VACOP-B group. The actuarial three-year progression-free survival was 35 +/- 10% for the MACOP-B group, 48 +/- 11% for the VACOP-B group, and 46 +/- 7% for all patients. Treatment mortality was 6%. A univariate and a multivariate analysis of selected pretreatment parameters and of regimen demonstrated that stage III or IV, high-grade lymphoma, and elevated serum LDH, but not the type of regimen, are significantly associated with poor progression-free survival in our patient population.
In Salmonella typhimurium, dnaQ null mutants (encoding the epsilon editing subunit of DNA polymerase III [Pol III]) exhibit a severe growth defect when the genetic background is otherwise wild type. Suppression of the growth defect requires both a mutation affecting the alpha (polymerase) subunit of DNA polymerase III and adequate levels of DNA polymerase I. In the present paper, we report on studies that clarify the nature of the physiological defect imposed by the loss of epsilon and the mechanism of its suppression. Unsuppressed dnaQ mutants exhibited chronic SOS induction, indicating exposure of single-stranded DNA in vivo, most likely as gaps in double-stranded DNA. Suppression of the growth defect was associated with suppression of SOS induction. Thus, Pol I and the mutant Pol III combined to reduce the formation of single-stranded DNA or accelerate its maturation to double-stranded DNA. Studies with mutants in major DNA repair pathways supported the view that the defect in DNA metabolism in dnaQ mutants was at the level of DNA replication rather than of repair. The requirement for Pol I was satisfied by alleles of the gene for Pol I encoding polymerase activity or by rat DNA polymerase beta (which exhibits polymerase activity only). Consequently, normal growth is restored to dnaQ mutants when sufficient polymerase activity is provided and this compensatory polymerase activity can function independently of Pol III. The high level of Pol I polymerase activity may be required to satisfy the increased demand for residual DNA synthesis at regions of single-stranded DNA generated by epsilon-minus pol III. The emphasis on adequate polymerase activity in dnaQ mutants is also observed in the purified alpha subunit containing the suppressor mutation, which exhibits a modestly elevated intrinsic polymerase activity relative to that of wild-type alpha.
The dnaB gene of Escherichia coli encodes an essential DNA replication enzyme. Fueled by the energy derived from the hydrolysis of ATP to ADP+P(i), this enzyme unwinds double-stranded DNA in advance of the DNA polymerase. While doing so, it intermittently stimulates primase to synthesize an RNA primer for an Okazaki fragment. To better understand the structural basis of these and other aspects of DnaB function, we have initiated a study of mutant DnaB proteins. Here, we report the purification and characterization of a mutant DnaB protein (RC231) containing cysteine in place of arginine at residue 231. The mutant protein attains a stable, properly folded structure that allows association of six promoters to form a hexamer, as is also true for wild-type DnaB. Further, the mutant protein interacts with ATP, the nonhydrolyzable ATP analog adenosine-5'-O-(3-thiotriphosphate) (ATP gamma S), ADP, and poly(dT), and it stimulates primase action. It is, however, profoundly deficient in ATP hydrolysis, helicase activity, and replication activity at the chromosomal origin of replication. In addition, while general priming reactions with wild-type DnaB and ATP elicited the synthesis of short primers, reactions with DnaB and ATP gamma S or with RC231 and either ATP or ATP gamma S stimulated the synthesis of significantly longer primers. On the basis of these observations, we suggest that primase interacts directly with DnaB throughout primer synthesis during general priming, until dissociation of DnaB from DNA or ATP hydrolysis by DnaB disrupts the interaction and leads to primer termination.
Prepubertal gilts of obese (n = 24) or lean (n = 24) genetic lines were injected (s.c.) daily with 0, 2, or 4 mg of porcine somatotropin (pST) for 6 wk starting at 160 d of age to determine whether pST affects follicular function. Blood and ovaries were collected at slaughter 24 h after the last injection. Surface follicles greater than or equal to 1.0 mm in diameter were counted, and pools of follicular fluid (FFL) and granulosa cells were collected from 1.0- to 3.9-mm (small) and 4.0- to 6.9-mm (medium) follicles. Oocytes were collected from small and medium follicles and evaluated for maturational stage and viability. Porcine somatotropin increased (P less than .08) the numbers of small but not the numbers of medium follicles per gilt (P greater than .10). Oocyte maturation and viability were not affected by pST or genetic line. Porcine somatotropin increased (P less than .05) concentrations of insulin-like growth factor I (IGF-I) in serum and FFL of both obese and lean gilts; IGF-I was lower (P less than .01) in lean gilts. Treatment with pST decreased (P less than .05) IGF-II in FFL of lean but not in that of obese gilts. Dose of pST and line had no effect on concentrations of progesterone in FFL of small or medium follicles or on concentrations of estradiol in FFL of small follicles.(ABSTRACT TRUNCATED AT 250 WORDS)
Report of a T-cell rich B-cell lymphoma (TCRBCL) in a 43 years old man with an associated haemophagocytic syndrome (HS). At presentation the haemophagocytic cells involved the same organs as the lymphoma, i.e. spleen, liver, abdominal lymph nodes and bone marrow. As supportive measure to alleviate chemotherapy-induced granulocytopenia the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) was given. After an initial improvement of the blood granulocyte count pancytopenia developed again, resulting in fatal sepsis. Autopsy demonstrated massive proliferation of macrophages in the bone marrow with haemophagocytosis as morphological correlation to the pancytopenia. The observation that exogenous GM-CSF enhanced the preexistent HS primarily reactive to the TCRBCL raises the question if endogenous GM-CSF may play a role in triggering a HS. The observed association of TCRBCL and HS has not been reported so far.
Tumoral calcinosis (TC) is a rare syndrome involving ectopic calcifications in the vicinity of the large joints. In about one third of patients the disorder is familial and is associated with hyperphosphatemia, elevation of 1,25-dihydroxy-vitamin-D levels and peculiar dental lesion. TC is inherited in an autosomal-recessive manner. In a normophosphatemic male patient with alcoholic cirrhosis of the liver, TC occurred first in the thoracic wall. Seven years after excision of the first lesion, a large tumor mass around the right hip developed. Infection of the calcified masses with Staph. aureus led to extensive abscess formation, septicemia and death at the age of 64. Clinical, dental and biochemical examination of the 7 descendants of the patient revealed no constitutional signs of the disease, thus identifying our patient as a sporadic case. Clinical and pathological findings in the patient are discussed and the literature is reviewed.
Collaboration of specialists is a prerequisite for the modern care of cancer patients. The 'tumor board' plays a central role. As a rule, close to 10% of all cancer patients of a hospital are reviewed by this panel. Patho-anatomic questions are settled and therapeutic plans established. A cooperative case review shortens decision paths, and therapeutic procedures are supported by all the participating specialists. The tumor board is also appreciated by postgraduate education, and it facilitates the introduction of oncologic thinking in the general hospital. For the specialist the incentive is to provide insight into his field, to expose advantages or weaknesses of his therapeutic modalities and to adapt them to the special needs of a particular patient.
According to the current model for mutagenic bypass of UV-induced lesions, efficient bypass requires three proteins: activated RecA (RecA*) and either activated UmuD (UmuD') and UmuC or their plasmid-encoded analogues, MucA' and MucB. RecA* aids synthesis of UmuD' and UmuC (and MucA'/MucB) at two levels: by inactivation of the LexA transcriptional repressor of these genes and by cleavage of UmuD (and MucA) to produce the active fragments, UmuD' (MucA'). A third role for RecA is revealed when these two roles are otherwise satisfied in a suitably engineered strain. An often-suggested possible role for RecA in bypass is inhibition of editing by the epsilon subunit of DNA polymerase III. Here, by demonstrating that elimination of epsilon by deletion of its gene, dnaQ, does not relieve the requirement for the third function of RecA, we show that RecA must perform some function other than, or in addition to, inhibition of epsilon. We also show that elimination of epsilon does not relieve the requirement for either Muc protein. Moreover, we observed reactivation of irradiated phi X174 in unirradiated cells expressing MucA' and MucB. This finding makes it unlikely that the additional role of recA involves derepression of an unidentified gene or cleavage of an unidentified protein and makes it more likely that RecA participates directly in bypass.
Selected synthetic oligoamines were able to inhibit (IC50) the growth of leukemic L 1210 cells in concentrations between 4-10 mumol/L. The essential structural features were at least two basic nitrogen functions in suitable distance, substituted with arylalkyl or alkyl groups. The favorable chain length is about eight carbon atoms. The cytostatic effect is complete after 30 min and cannot be washed out with buffer. Viability measurements showed that the leukemic cells were killed in a time dependent manner. As no influence on the cell nucleus could be observed this is most probably due to interaction with the cell membrane. When high local concentrations are applied in vivo, the oligoamines are toxic because of cytolytic properties. This toxicity can be overcome by administration of suitable prodrugs (LD50 greater than 1000 mg/kg).
Solid-cystic (papillary-cystic) tumours (SCT) of the pancreas are distinctive neoplasms with a predilection for young female patients. This is the first detailed report describing the occurrence of SCT in two young male patients. Except for the extapancreatic occurrence of one of the tumours (in the retroperitoneal region behind the head of the pancreas), all other clinicopathological features were identical to those characterizing the SCT in women. Immunostaining was (at least focally) positive for Lu 5 (broad spectrum keratin marker), vimentin and alpha-1-antitrypsin. The tumours were negative for neuroendocrine markers (except for neuron-specific enolase), pancreatic hormones and enzymes, pancreatic stone protein, carcinoembryonic antigen, CA 19-9 and nuclear oestrogen and progesterone receptors. This report does not support the suggested female sex hormone dependence of SCT.
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We report on a case of perhexiline maleate-induced hepatitis secondary to a long-term administration of recommended daily dosages of 300 mg. The patient had a spectacular weight loss of 29 kg. He developed hepatitis, which subsided after drug withdrawal. Our electron-microscopic findings with the typical inclusion bodies and impaired hydroxylation capacity point to an underlying metabolic disorder as the pathogenetic mechanism.
In a short-distance homing task, golden hamsters derive the homing direction both from visual extra-maze cues and from the integration of the outward journey. The relative importance of visual configurations in the control of homing was assessed by presenting these cues in conflict with path integration. The hamsters depended mainly on path integration during the presentation of 3 objects at the periphery of the experimental arena or of a background pattern which surrounded the arena at a certain distance. However, they switched to visually controlled behaviour when the objects were superimposed on the patterned background. The possibility is discussed that the enhancement of the depth dimension through the simultaneous presentation of a foreground and a background may increase the effectiveness of visual cues in spatial orientation.
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