Dead reckoning in a small mammal: the evaluation of distance

When hoarding food under infra-red light, golden hamsters Mesocricetus auratus W. return fairly directly from a feeding place to their nest site by evaluating and updating internal signals that they have generated during the previous outward journey to the feeding place. To test more specifically the animals' capacity to evaluate the linear components of the outward journey, the subjects were led from their (cone-shaped) nest to a feeding place along a detour which comprised either 2 (experiment 1) or 5 (experiment 2) segments; adjoining segments were at right angles to each other. In these conditions, the subjects remained significantly oriented towards the nest and therefore were capable of assessing translations as well as rotations during the outward journey. In experiment 3, the nest was removed after the hamsters had started the direct outward journey to the feeding place and the hamsters were rotated during the food uptake. The animals were no longer oriented towards the starting point of their journey, but nonetheless covered, along a fairly straight path, the correct homing distance, and then changed over to a circular search path. These results confirm that mammals can derive the linear components of an outward journey from self-generated signals and therefore are able to judge the homing distance without relying on cues from the environment. For a number of detour outward journeys, our data yield an unexpectedly good fit to Müller and Wehner's (1988) model of dead reckoning in ants. However, this is no longer the case when the outward journey contains an initial loop which brings the subject back to the starting point. These findings are discussed in terms of the biological significance and limitations of an approximate form of path integration.

[Suspected adult-onset Still's disease: unexpected manifestation of leprosy]

A 23-year old male from Sri Lanka was admitted to hospital with symmetrical inflammatory peripheral polyarthritis, fever of 39 degrees C and poly-lymphadenopathy. At first we suspected adult onset Still's disease. The histological findings from axillary lymph node biopsy strongly suggested the diagnosis of leprosy, for which we had had little evidence thus far. Typical skin lesions were absent, skin smears were negative and neurological symptoms only became obvious much later when fever and arthritis had subsided under anti-inflammatory treatment. At this time a right ulnar palsy developed, with atrophy of the interosseous muscles and thickening of the ulnar nerves at both medial epicondyles. Fite-stains of a sural nerve biopsy confirmed the diagnosis when mycobacteria were detected. Leprosy displays a clinico-pathological spectrum caused by variations in host resistance. A widely accepted classification is the five group system of Ridley and Jopling. At one extreme of this spectrum are patients with lepromatous or low resistance leprosy with numerous bacilli, and at the other those with high resistance or tuberculous leprosy where few or no bacilli are found. The numerous bacilli in the sural nerve biopsy classified the disease as lepromatous in our case. Of the various manifestations of the lepra reaction occurring in lepromatous leprosy, one is acute arthritis, but a more common one is erythema nodosum leprosum. Our patient's clinical presentation was interpreted to be a rheumatic manifestation of a type-2 reaction. This form of immunological response in leprosy is an immune complex syndrome and may mimic different rheumatic diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and characterization of a mutant DnaB protein specifically defective in ATP hydrolysis

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.

DNA replication defect in Salmonella typhimurium mutants lacking the editing (epsilon) subunit of DNA polymerase III

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.

Effect of porcine somatotropin on number of granulosa cell luteinizing hormone/human chorionic gonadotropin receptors, oocyte viability, and concentrations of steroids and insulin-like growth factors I and II in follicular fluid of lean and obese gilts

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)

Chemotherapy with MACOP-B and VACOP-B for intermediate- and high-grade non-Hodgkin's lymphoma: clinical results and analysis of prognostic factors

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.

[Liposarcoma of the laryngeal region. Case report and literature review]

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.

[Large myelolipoma with reversible hypertension]

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.

A rare entity among childhood malignant lymphomas (large anaplastic T-cell Ki-1 +)

A case of peripheral type T-cell lymphoma is presented to underline the difficulty in distinguishing the initial clinical findings of an inflammatory neoplastic disorder since the diagnosis could only be arrived at after several repeated lymph node biopsies. An 11 10/12-year-old boy admitted to the hospital with inguinal lymph node enlargement was diagnosed as having adenitis and periadenitis. The disease had progressed and the patient had remittent fever rising to 39 degrees C, and another biopsy was taken. Cervical lymphadenomegaly was present, A diagnosis of chronic lymphadenitis with lymphocyte loss and fibrosis was established. The diagnosis could only be made from biopsy material taken from the deep cervical (jugularis interna) and axillary lymph nodes one year later, which showed Ki-1 antigen positive large T-cell lymphoma. The disease showed continuous activity in spite of chemotherapy and the child survived only 17 months.

Platelet aggregation inhibiting and anticoagulant effects of oligoamines, XVI: Cytostatic and cytotoxic side effects of oligoamines

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).

[Tumoral calcinosis with superinfection and sepsis]

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.

Perhexiline maleate-induced hepatitis

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.

Solid-cystic (papillary-cystic) tumours within and outside the pancreas in men: report of two patients

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.

[Interdisciplinary team work from the viewpoint of the medical oncologist]

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.

Requirements for bypass of UV-induced lesions in single-stranded DNA of bacteriophage phi X174 in Salmonella typhimurium

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.

Enhancing the impact of visual extra-maze cues in a spatial orientation task

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.

Nucleotide sequences of dnaE, the gene for the polymerase subunit of DNA polymerase III in Salmonella typhimurium, and a variant that facilitates growth in the absence of another polymerase subunit

The dnaE gene of Salmonella typhimurium, like that of Escherichia coli, encodes the alpha subunit containing the polymerase activity of the principal replicative enzyme, DNA polymerase III. This gene, or one nearby, has been identified as the locus of suppressor mutations that promote growth by cells deleted for dnaQ, the gene for the editing subunit of this enzyme complex. Using a combination of nucleotide sequencing and marker rescue experiments, the alteration in one such suppressor was identified as a valine-to-glycine substitution at amino acid 832 of the 1,160-amino-acid alpha polypeptide. The alpha polypeptides of E. coli and S. typhimurium are identical in size and in 97% of their amino acid residues. Their identity includes the valine residue that was changed in the suppressor allele of S. typhimurium. We also localized a temperature-sensitive dnaE mutation to the 3' half of dnaE.

Isolation and characterization of mutants with deletions in dnaQ, the gene for the editing subunit of DNA polymerase III in Salmonella typhimurium

dnaQ (mutD) encodes the editing exonuclease subunit (epsilon) of DNA polymerase III. Previously described mutations in dnaQ include dominant and recessive mutator alleles as well as leaky temperature-sensitive alleles. We describe the properties of strains bearing null mutations (deletion-substitution alleles) of this gene. Null mutants exhibited a growth defect as well as elevated spontaneous mutation. As a consequence of the poor growth of dnaQ mutants and their high mutation rate, these strains were replaced within single colonies by derivatives carrying an extragenic suppressor mutation that compensated the growth defect but apparently not the mutator effect. Sixteen independently derived suppressors mapped in the vicinity of dnaE, the gene for the polymerization subunit (alpha) of DNA polymerase III, and one suppressor that was sequenced encoded an altered alpha polypeptide. Partially purified DNA polymerase III containing this altered alpha subunit was active in polymerization assays. In addition to their dependence on a suppressor mutation affecting alpha, dnaQ mutants strictly required DNA polymerase I for viability. We argue from these data that in the absence of epsilon, DNA replication falters unless secondary mechanisms, including genetically coded alteration in the intrinsic replication capacity of alpha and increased use of DNA polymerase I, come into play. Thus, epsilon plays a role in DNA replication distinct from its known role in controlling spontaneous mutation frequency.