Synthesis, chemical behavior, structure elucidation and iNOS inhibitory activity of 1-substituted 3-methylsulfanyl-5,6,7,8-tetrahydro-1H-[1,2,4]triazolo[1,2-a]pyridazines.

Novel slim and shapely sp3-rich nitrogen containing heterocyclic ring systems are sought-after platforms for the expansion of molecular diversity in lead discovery. The present work describes the synthesis and characterization of a series of derivatives of hitherto unknown 3-methylsulfanyl-5,6,7,8-tetrahydro-1H-[1,2,4]triazolo[1,2-a]pyridazines 2. This approach was guided by a computational study, aiming at an optimization of previously reported [1,2,4]triazolo[1,2-a]pyridazine-1-thiones 1 known to inhibit the inducible nitric oxide synthase (iNOS). The title compounds are accessible by methylation of compounds 1 under mild conditions. The products were biologically evaluated by the same cell-based assay as applied for previous products of type 1 using RINm5F cells, which were stimulated to produce NO on the influence of proinflammatory cytokines IL-1ß and IFN-γ. Compounds 2 did not display the anticipated improved iNOS inhibitory activity in the selected assay but contribute to SAR in the field. In addition, an unprecedented formation of side-products 3 via oxidation has been investigated. The novel scaffolds represent attractive starting points for the construction of diverse molecules which differ considerably from known compounds based on flat and lipophilic aromatic scaffolds.

[Perampanel in the treatment of a patient with glioblastoma multiforme without IDH1 mutation and without MGMT promotor methylation]. / Perampanel in der Behandlung eines Patienten mit Glioblastoma multiforme ohne IHD-1-Mutation und ohne MGMT-Promotor-Methylierung.

Malignant gliomas like glioblastoma multiforme (GBM) release glutamate which causes excitotoxic death to surrounding neurons, thereby vacating room for tumor expansion. We report the case of a patient with GBM treated with the AMPA receptor blocker Perampanel (PER) in combination therapy for partial seizures. Histological work-up of a biopsy showed the tissue of a GBM without mutation of the isocitrate dehydrogenase 1 (IDH1) and without promotor methylation of the O6-methylguanine-DNA methyltransferase (MGMT). In a group of patients with IDH 1 wild type and non-methylated MGMT a median survival of 199 days after surgery (i. e. 6.5 months) was described. Our patient lived about one year longer. PER rendered our patient seizure-free for at least the last seven months of his life. It was well tolerated and did not increase the toxicity of temozolomide. When choosing an antiepileptic drug (AED) for the treatment of seizures in patients with malignant brain tumors, the efficacy, the tolerability and perhaps possible effects on tumor progression of the AED should be taken into account.

Sonographic detection of basal ganglia abnormalities in spasmodic dysphonia.

BACKGROUND AND PURPOSE: Abnormalities of the lenticular nucleus (LN) on transcranial sonography (TCS) are a characteristic finding in idiopathic segmental and generalized dystonia. Our intention was to study whether TCS detects basal ganglia abnormalities also in spasmodic dysphonia, an extremely focal form of dystonia. METHODS: Transcranial sonography of basal ganglia, substantia nigra and ventricles was performed in 14 patients with spasmodic dysphonia (10 women, four men; disease duration 16.5 ± 6.1 years) and 14 age- and sex-matched healthy controls in an investigator-blinded setting. RESULTS: Lenticular nucleus hyperechogenicity was found in 12 spasmodic dysphonia patients but only in one healthy individual (Fisher's exact test, P < 0.001) whilst other TCS findings did not differ. The area of LN hyperechogenic lesions quantified on digitized image analysis correlated with spasmodic dysphonia severity (Spearman test, r = 0.82, P < 0.001). CONCLUSION: Our findings link the underlying pathology of spasmodic dysphonia to that of more widespread forms of dystonia.

Interhemispheric inhibition in different phenotypes of progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is the most common atypical parkinsonian syndrome and an important differential diagnosis of parkinson's disease (PD). The clinical diagnosis of PSP relies on characteristic symptoms. There is evidence of clinical subgroups within the entity of PSP interfering with making the firm diagnosis. It was the aim of the study to clarify the differences between phenotypical subtypes of PSP and PD focusing on transcallosal inhibition (TI). A systematic chart review of 67 patients supposed to have probable PSP was done in a standardized diagnostic work-up. As only complete data sets were included into further analysis, 26 PSP patients (mean age 68.6 ± 7.1 years) could be evaluated and subdivided into Richardson's syndrome (RS) (n = 15) or PSP of parkinsonian type (PSP-P) (n = 11). Fifteen PD patients served as controls. TI was evaluated by investigation of the ipsilateral silent period (iSP) with transcranial magnetic stimulation (TMS). Cognition was assessed by the Addenbrooke's cognitive examination (ACE-R). TMS revealed a significantly more severe affection of TI in RS patients as compared to PSP-P and PD patients who showed similar neurophysiological findings. 47 % of RS patient displayed an iSP loss, whereas PSP-P and PD did not. There was a significant correlation between iSP latency and ACE-R (Spearman's coefficient -0.369, P = 0.010). In conclusion, RS patients-contrary to PSP-P and PD patients-had pathological TI at least in one hemisphere indicating more severe involvement of transcallosally projecting output neurons in RS.

Insular stroke is associated with acute sympathetic hyperactivation and immunodepression.

BACKGROUND AND PURPOSE: Post-stroke immunodepression has been related to brain lesion size but not a specific lesion location. Here, we studied the influence of lesion location within middle cerebral artery (MCA) territory on parameters related to activation of sympathetic adrenomedullar pathway, immunodepression, and associated infection. METHODS: We analyzed clinical, brain imaging, and laboratory data of 384 patients (174 women; mean age 70.8 ± 12.9 years) consecutively admitted to the stroke unit no later than 24 h after onset of acute ischaemic stroke involving the MCA territory. RESULTS: Patients with lesion affecting >33% of MCA territory had increased serum metanephrine and normetanephrine levels, elevated neutrophil counts but decreased eosinophil, helper T lymphocyte, and cytotoxic T lymphocyte counts compared to patients with lesion in <33% of MCA territory. Patients with large infarctions had increased frequency of infections within 14 days after stroke, especially chest infections (P < 0.001). Considering only patients with non-lacunar infarction in <33% of MCA territory, those with insular lesion had significantly higher normetanephrine levels, higher neutrophil but lower eosinophil and helper T lymphocyte counts than those with non-insular lesion, despite similar lesion diameters. This coincided with an increased frequency of chest infections (P < 0.01) in patients with insular lesion. Whilst patients with right insular lesion showed decreased heart rate variability, lesion laterality had no impact on laboratory findings or infection frequency. CONCLUSION: These findings suggest a specific role of insular lesion in the pathogenesis of stroke-induced sympathetic hyperactivation and immunodepression. Neuroimaging studies applying lesion volume calculation techniques are warranted to confirm these findings.

Recurrent aphasic status epilepticus after prolonged generalized tonic-clonic seizures versus a special feature of Todd's paralysis.

Postictal aphasia may be a feature of Todd's paralysis or the presentation of aphasic nonconvulsive status epilepticus (NCSE). We describe a 74-year-old woman with three episodes of aphasic status epilepticus after prolonged generalized tonic-clonic seizures. In the first episode, the NCSE was not definitively diagnosed, but an increase in the epileptic medication led to resolution of the epileptic activity within 2 weeks. During the second episode, NCSE was terminated within 7 days under intensified antiepileptic treatment. In the third episode, phenytoin treatment led to intoxication and resulted in further treatment on an intensive care unit. The patient required several months to recover from this episode. NCSE in the elderly is difficult to recognize, especially when it presents as a prolonged postictal deficit like aphasia. Once diagnosed it has to be treated carefully, because in the elderly, aggressive treatment strategies may be associated with a high risk of adverse events.

Thrombopoietin expands erythroid progenitors, increases red cell production, and enhances erythroid recovery after myelosuppressive therapy.

Thrombopoietin (TPO), the ligand for the receptor protooncogene c-mpl, has been cloned and shown to be the critical regulator of platelet production. Several features of c-Mpl expression, including its presence on erythroid cell lines, and the panmyeloid transformation characteristic of myeloproliferative leukemia (MPL) viral disease led us to investigate whether this receptor-ligand system may play a role in erythropoiesis. We report that although TPO alone did not support the growth of either early or late erythroid progenitors, it acted in synergy with erythropoietin to expand these populations. Moreover, while the effects on erythropoiesis in normal animals were modest, TPO greatly expanded the number of erythroid progenitors and blood reticulocytes and was associated with accelerated red cell recovery in myelosuppressed mice. Together, these data strongly suggest that erythroid progenitors respond to TOP and that this newly cloned cytokine, critical for platelet production, can augment erythropoiesis in states of marrow failure.

Activated MEK cooperates with Cdkn2a and Pten loss to promote the development and maintenance of melanoma.

The development of targeted inhibitors, vemurafenib and dabrafenib, has led to improved clinical outcome for melanoma patients with BRAFV600E mutations. Although the initial response to these inhibitors can be dramatic, sometimes causing complete tumor regression, the majority of melanomas eventually become resistant. Mitogen-activated protein kinase kinase (MEK) mutations are found in primary melanomas and frequently reported in BRAF melanomas that develop resistance to targeted therapy; however, melanoma is a molecularly heterogeneous cancer, and which mutations are drivers and which are passengers remains to be determined. In this study, we demonstrate that in BRAFV600E melanoma cell lines, activating MEK mutations drive resistance and contribute to suboptimal growth of melanoma cells following the withdrawal of BRAF inhibition. In this manner, the cells are drug-addicted, suggesting that melanoma cells evolve a 'just right' level of mitogen-activated protein kinase signaling and the additive effects of MEK and BRAF mutations are counterproductive. We also used a novel mouse model of melanoma to demonstrate that several of these MEK mutants promote the development, growth and maintenance of melanoma in vivo in the context of Cdkn2a and Pten loss. By utilizing a genetic approach to control mutant MEK expression in vivo, we were able to induce tumor regression and significantly increase survival; however, after a long latency, all tumors subsequently became resistant. These data suggest that resistance to BRAF or MEK inhibitors is probably inevitable, and novel therapeutic approaches are needed to target dormant tumors.

Neuromyelitis optica spectrum disorder coinciding with hematological immune disease: A case report.

INTRODUCTION: Recently defined consensus criteria for the diagnosis of neuromyelitis optica spectrum disorders (NMOSD) allow establishing the diagnosis in patients without elevated AQP4-Ab and optic nerve involvement. According to the new extended definition, NMOSD is closely associated with extensive spinal cord inflammation occurring in the course of systemic autoimmune diseases as sarcoidosis or lupus erythematodes. NMOSD occurring in the course of hematological disease have not yet been reported in the literature. CASE REPORT: A 38 year old male subsequently developed thrombocytopenia, hemolytic anemia and agranulocytosis over a 23 month period. Three months after an episode of agranulocytosis, he noticed ascending sensory disturbances and progressive weakness of his legs. Within two days, symptoms worsened to give almost complete paraplegia and loss of sensation below a midthoracic level. MRI revealed signal hyperintensity and edema in T2-weighted sequences reaching from the 2nd cervical to the 9th thoracic vertebral body. Two years later, he developed a second episode with lesions in the spinal cord and periventricular areas of brain stem and thalamus. CONCLUSION: The relapsing time course and the topographical pattern of central nervous system lesions restricted to axial brain structures and the spinal cord fulfill the criteria that have recently been defined for AQP4-Ab-negative NMO-spectrum disease. Systematic studies on the association of hematological autoimmune phenomena and spinal cord disease are needed to clarify whether this coincidence is just a casual phenomenon or whether it points to a yet undiscovered but perhaps therapeutically interesting link of immunological mechanisms affecting both organ systems.

Erectile function after treatment for rhabdomyosarcoma of prostate and bladder.

INTRODUCTION: Rhabdomyosarcoma (RMS) accounts for 5% of all pediatric tumors; 15-20% of these tumors are located in the urogenital tract, mostly originating from the prostate or bladder. In the light of the steadily improving prognosis for patients with RMS through interdisciplinary-multimodal study protocols with 60-70% long-term survivors, non oncological aspects such as erectile function (EF) have become increasingly important. The aim of this study was to evaluate EF in patients having undergone treatment for RMS of the bladder and prostate. DESIGN: The medical records of 24 male patients having undergone surgical treatment for pelvic RMS between 1975 and 2014 were reviewed, and follow-up was obtained. Erectile function was determined using the Self-Estimation Index of Erectile Function-No Sexual Intercourse (SIEF-NS) and the Erection Hardness Scale (EHS). Potential prognostic factors were evaluated in respect to their impact on EF. RESULTS: Thirteen patients were included in the study (median age 20 years). Median follow-up period was 12.7 years (1.09-39.85). All patients completed the EHS; nine patients completed the SIEF-NS. All three patients with preserved erectile function (EHS = 4) showed a score indicating no or minimal impairment on sexual function on SIEF-NS (median 33). None of these patients had undergone external radiotherapy, and radical cystoprostatectomy had been performed before the third year of life in two out of three. The remaining patients had erectile dysfunction (EHS = 0). Three patients had an unsatisfying treatment attempt with sildenafil. Seven patients, including all with failures of oral PDE-5-inhibitors, were successfully treated with intracavernous injection of Alprostadil (Summary Table). DISCUSSION: This was the largest study, to date, evaluating erectile EF in patients treated for RMS of the bladder or prostate. EF was preserved in some patients, despite aggressive treatment modalities. Patients affected by erectile dysfunction after therapy showed limited response to PDE-5 inhibitors, but even after failure of the latter, an intracavernous injection of Alprostadil showed a significant improvement in EHS and SIEF-NS. Limitations of the study included the retrospective nature, small sample size, and heterogeneity of underlying disease, stage, and treatment modalities used. CONCLUSIONS: The results suggested that in a subset of patients, EF was preserved after radical surgical treatment of RMS, especially in young boys. Intracavernous injection of Alprostadil was effective, even after failure of PDE-5-inhibitors, and should be offered to patients without spontaneous erections, whereas PDE-5-inhibitors appeared to be largely ineffective. External radiation therapy appeared to have a negative impact on EF.

Enhanced transmembrane signalling activity of monoclonal antibody heteroconjugates suggests molecular interactions between receptors on the T cell surface.

Signal transduction occurs through multiple receptors expressed on mature, resting T cells. In addition to the CD3-T cell receptor complex, the CD2, CD4, CD5, CD7, CD8 and CD28 receptors mobilize cytoplasmic calcium within minutes of binding with monoclonal antibodies and additional crosslinking occurs on the cell surface. As an approach to study the interactions between these receptors and their transduced signals, monoclonal antibodies to each of these receptors were covalently coupled as heteroconjugates and investigated for activity in cytoplasmic calcium mobilization using indo-1 and flow cytometry. Of a total of 35 conjugates studied, there were seven heteroconjugates that showed an increase in activity and these consisted of either certain conjugates of anti-CD3 or certain conjugates of anti-CD5. The CD3-CD2, CD3-CD4, CD3-CD6 and CD3-CD8 heteroconjugates each gained two to three orders of magnitude in titer in calcium mobilization compared to unconjugated CD3 or the CD3-CD3 conjugate. The increase in activity was not accompanied by an increase in binding titer, indicating that signal transduction occurred at lower levels of receptor occupancy. The increased activity was dependent in each case on the relevant second receptor, since unconjugated CD2, CD4, CD6 or CD8 MAb could block the activity of the corresponding heteroconjugate. Neither CD3-CD5, CD3-CD28 or CD3-CD3 conjugates gained activity, whereas CD3-CD7 heteroconjugates gained slightly in activity. The heteroconjugates with CD5 that acquired ability to mobilize calcium at low concns (less than 5 micrograms/ml) were CD5-CD4, CD5-CD8 and CD5-CD6. Their activity could be inhibited by either CD5 MAb or the second MAb of the heteroconjugate. The increased activity of CD3 or CD5 heteroconjugates was observed in the absence of extracellular calcium. Size exclusion chromatography of heteroconjugates demonstrated that 1:1 ratios were optimal, but larger conjugates were also active. These results suggest that certain receptors are capable for molecular interactions on the cell surface to form complexes with enhanced activity in signal transduction leading to calcium mobilization.

Thrombopoietin expands erythroid, granulocyte-macrophage, and megakaryocytic progenitor cells in normal and myelosuppressed mice.

Thrombopoietin (Tpo), the ligand for the proto-oncogene receptor c-Mpl, increases megakaryocyte size, ploidy, and surface expression of platelet-specific glycoproteins, is inversely related to platelet mass, and is a potent in vivo stimulus of platelet production. However, several features of c-mpl biology, and that of its viral counterpart v-mpl, suggest that the action of Tpo may not be strictly limited to megakaryocytopoiesis. To investigate the possibility that Tpo might affect a multitude of cell lineages, we studied the effects of in vivo administration of the hormone on multiple types of marrow and splenic clonogenic hematopoietic progenitors. We report that Tpo acts to expand BFU-E, CFU-GM, and CFU-Mk and redistribute CFU-E in normal mice and to hasten the recovery of all of these progenitor cell types in myelosuppressed animals. These findings argue that the hematopoietic progenitor cell compartment responds to Tpo as a whole and that the in vivo effects of Tpo administration may be more wide-ranging than previously anticipated.

Thrombopoietin accelerates platelet, red blood cell, and neutrophil recovery in myelosuppressed mice.

The recent cloning of thrombopoietin (TPO) has allowed us to study its in vivo effects in normal and myelosuppressed mice. Normal Balb/c mice were treated with recombinant human TPO (hTPO) at doses ranging from 1 to 20 kU for 7 days, and complete blood counts (CBCs) and the number of megakaryocytes in the bone marrow were determined. Platelet counts were increased starting on day 5 after mice were treated with hTPO. Platelet counts reached a peak between days 8 and 11 and returned to baseline between days 16 and 20. hTPO treatment increased the number of megakaryocytes in the bone marrow starting on day 3. In normal mice, hTPO treatment did not affect red or white blood cell (RBC or WBC) counts. To test the effects of hTPO in myelosuppressed mice, Balb/c mice were irradiated with 350 cGy total-body irradiation and dosed with 1.2 mg carboplatin, resulting in severe and prolonged thrombocytopenia, anemia, and neutropenia. Treatment with 5-20 kU hTPO for 7 days accelerated the recovery of platelet, RBC, and neutrophil counts in myelosuppressed mice and also significantly improved their nadirs. In addition, bone marrow megakaryocyte numbers recovered 11 days earlier and reticulocyte counts recovered 10 days earlier in hTPO-treated myelosuppressed mice than in controls. These results indicate that TPO can improve hematopoietic recovery in myelosuppressed mice, affecting multiple cell lineages.

[Continent urinary diversion following anterior exenteration]. / Kontinente Harnableitung nach vorderer Exenteration.

BACKGROUND: Quality of life after anterior or total exenteration is determined, among other factors, by the type of urinary diversion. There are two different types of urinary diversion: incontinent diversion (ureterocutaneostomy, ileal conduit, and colonic conduit) and continent diversions (continent cutaneous pouch, orthotopic neobladder, and rectal reservoir). RESULTS: Invasive bladder cancer and advanced or recurrent gynecological tumors are the main indications for continent urinary diversion in women. In patients with non-irradiated bladder cancer, an orthotopic neobladder (except those with tumor invasion of the bladder neck or urethra) or a rectal reservoir is an option. In patients who had received preoperative radiotherapy, non-irradiated bowel segments should be used for urinary diversion (e.g., the transverse colon). In patients with planned postoperative radiation, the urinary diversion should be outside the radiation field. CONCLUSION: Advantages and disadvantages of all types of urinary diversion should be objectively discussed with the patient. Especially exenteration for advanced or recurrent gynecological cancers should be performed in centers with a multidisciplinary team (gynecologist, urologist, radiotherapist, and in cases with complete exenteration the gastrointestinal surgeon).

Intracellular calcium response is reduced in CD4+ lymphocytes in Alzheimer's disease and in older persons with Down's syndrome.

Abnormalities in intracellular free calcium ([Ca2+]i) regulation are likely to play a role in brain aging and have been described in cells from patients with Alzheimer's disease (AD). [Ca2+]i acts as a second messenger in transmembrane signaling and regulates diverse functions in many cell types. Therefore, abnormalities in [Ca2+]i response may have far-ranging effects. Using flow cytometric assay for [Ca2+]i, we examined whether mitogen-induced increases in [Ca2+]i are abnormal in CD4+ T-lymphocytes from patients with familial AD (FAD), other AD, and Down's syndrome (DS) compared to age-matched controls. We observed that the peak [Ca2+]i responses were significantly decreased in CD4+ cells from 6 FAD patients (59% of control), 34 other AD patients (69% of age-matched control), and 6 older persons with DS (> 25 years old, 47% of control), after stimulation with 10 micrograms/ml anti-CD3 monoclonal antibody (mAb). The number of CD3 receptors on T lymphocytes of the AD patients was not decreased. In contrast, lymphocytes from subjects with FAD, other AD and older DS patients had no decrease in response to phytohemagglutinin (30 micrograms/ml). CD3 and related classes of membrane receptors are present on many cells of the central nervous system. Therefore, receptor signaling defects via this receptor in T lymphocytes of AD patients may be relevant to the central nervous system pathology seen in AD and DS.

Catalytic domains of tyrosine kinases determine the phosphorylation sites within c-Cbl.

Catalytic (SH1) domains of protein tyrosine kinases (PTKs) demonstrate specificity for peptide substrates. Whether SH1 domains differentiate between tyrosines in a physiological substrate has not been confirmed. Using purified proteins, we studied the ability of Syk, Fyn, and Abl to differentiate between tyrosines in a common PTK substrate, c-Cbl. We found that each kinase produced a distinct pattern of c-Cbl phosphorylation, which altered the phosphotyrosine-dependent interactions between c-Cbl and CrkL or phosphatidylinositol 3'-kinase (PI3-K). Our data support the concept that SH1 domains determine the final sites of phosphorylation once PTKs reach their target proteins.

Human nerve growth factor beta (hNGF-beta): mammary gland specific expression and production in transgenic rabbits.

Transgenic rabbits carrying gene constructs encoding human nerve growth factor beta (hNGF-beta) cDNA were generated. Expression of hNGF-beta mRNA was restricted to the mammary gland of lactating rabbits. Western Blot analysis revealed a polypeptide of 13.2 kDa in the milk of transgenic animals. hNGF-beta was purified from the milk by a two-step chromatographic procedure. Electrospray mass spectroscopy analysis of purified hNGF-beta depicted a molecular weight of 13,261 Da per subunit. The biological activity of the hNGF-beta was tested using PC12W2 cells and cultures of dorsal root ganglion neurons from chicken embryos. Crude defatted milk from transgenic animals and purified hNGF-beta demonstrated full biological activity when compared to commercial recombinant hNGF-beta.

Stabilization of erythrocytes by aldehydes and suitability of chicken IgY for the detection of potato virus X (PVX) in avidin-biotin enhanced reverse passive haemagglutination.

Methods are described for the detection of potato virus X (PVX) by reverse passive haemagglutination (RPH) by means of polyclonal antiviral antibodies coupled to sheep red blood cells (sRBC) and the chromic chloride method. The cells were stabilized with pyruvic aldehyde, thus providing a stock suspension for numerous coupling experiments lasting several months. Anti-PVX IgY, which is readily isolated in large amounts from the egg yolk of immunized chickens, was used in an avidin-biotin enhanced RPH assay with stabilized sRBC. With this method the PVX detection rate achieved was comparable to that of RPH assays using fresh non-fixed sRBC. In addition, avidin-coated sRBC could be stored for weeks at 4 degrees C and subsequently used for coupling with biotinylated IgY.

Rate matrices for analyzing large families of protein sequences.

We propose and study a new approach for the analysis of families of protein sequences. This method is related to the LogDet distances used in phylogenetic reconstructions; it can be viewed as an attempt to embed these distances into a multidimensional framework. The proposed method starts by associating a Markov matrix to each pairwise alignment deduced from a given multiple alignment. The central objects under consideration here are matrix-valued logarithms L of these Markov matrices, which exist under conditions that are compatible with fairly large divergence between the sequences. These logarithms allow us to compare data from a family of aligned proteins with simple models (in particular, continuous reversible Markov models) and to test the adequacy of such models. If one neglects fluctuations arising from the finite length of sequences, any continuous reversible Markov model with a single rate matrix Q over an arbitrary tree predicts that all the observed matrices L are multiples of Q. Our method exploits this fact, without relying on any tree estimation. We test this prediction on a family of proteins encoded by the mitochondrial genome of 26 multicellular animals, which include vertebrates, arthropods, echinoderms, molluscs, and nematodes. A principal component analysis of the observed matrices L shows that a single rate model can be used as a rough approximation to the data, but that systematic deviations from any such model are unmistakable and related to the evolutionary history of the species under consideration.