The analgesic and anti-inflammatory effects of Salvinorin A analogue ß-tetrahydropyran Salvinorin B in mice.

BACKGROUND: Drugs activating the mu opioid receptor are routinely used to treat severe acute and chronic pain. Unfortunately, side effects including nausea, constipation, respiratory depression, addiction and tolerance can limit clinical utility. In contrast, kappa opioid receptor (KOPr) agonists, such as Salvinorin A (SalA), have analgesic properties with little potential for abuse. METHODS: We evaluated SalA and the novel analogue ß-tetrahydropyran Salvinorin B (ß-THP SalB) for the ability to modulate pain and inflammation in vivo. The hot water tail-withdrawal assay, intradermal formalin-induced inflammatory pain and paclitaxel-induced neuropathic pain models were used to evaluate analgesic properties in mice. Tissue infiltration of inflammatory cells was measured by histology and flow cytometry. RESULTS: ß-tetrahydropyran Salvinorin B produced a longer duration of action in the tail-withdrawal assay compared to the parent compound SalA, and, like SalA and U50,488, ß-THP SalB is a full agonist at the KOPr. In the formalin-induced inflammatory pain model, ß-THP SalB and SalA significantly reduced pain score, paw oedema and limited the infiltration of neutrophils into the inflamed tissue. ß-THP SalB and SalA supressed both mechanical and cold allodynia in the paclitaxel-induced neuropathic pain model, in a dose-dependent manner. CONCLUSIONS: Structural modification of SalA at the C-2 position alters its analgesic potency and efficacy in vivo. Substitution with a tetrahydropyran group at C-2 produced potent analgesic and anti-inflammatory effects, including a reduction in paclitaxel-induced neuropathic pain. This study highlights the potential for KOPr agonists as analgesics with anti-inflammatory action and little risk of abuse. SIGNIFICANCE: Salvinorin A and the novel analogue ß-THP Salvinorin B show analgesic effects in the tail-withdrawal and formalin assays. They reduce oedema and decrease neutrophil infiltration into inflamed tissue, and suppress mechanical and cold allodynia in paclitaxel-induced neuropathic pain.

The loss of CCR6+ and CD161+ CD4+ T-cell homeostasis contributes to disease progression in SIV-infected rhesus macaques.

Although previous studies have shown that CD4+ T cells expressing CCR6 and CD161 are depleted from blood during HIV infection, the mechanisms underlying their loss remain unclear. In this study, we investigated how the homeostasis of CCR6+ and CD161+ CD4+ T cells contributes to SIV disease progression and the mechanisms responsible for their loss from circulation. By comparing SIV infection in rhesus macaques (RMs) and natural host sooty mangabeys (SMs), we found that the loss of CCR6+ and CD161+ CD4+ T cells from circulation is a distinguishing feature of progressive SIV infection in RMs. Furthermore, while viral infection critically contributes to the loss of CD161+CCR6-CD4+ T cells, a redistribution of CCR6+CD161- and CCR6+CD161+CD4+ T cells from the blood to the rectal mucosa is a chief mechanism for their loss during SIV infection. Finally, we provide evidence that the accumulation of CCR6+CD4+ T cells in the mucosa is damaging to the host by demonstrating their reduction from this site following initiation of antiretroviral therapy in SIV-infected RMs and their lack of accumulation in SIV-infected SMs. These data emphasize the importance of maintaining CCR6+ and CD161+ CD4+ T-cell homeostasis, particularly in the mucosa, to prevent disease progression during pathogenic HIV/SIV infection.

A one-dimensional mixed porohyperelastic transport swelling finite element model with growth.

A one-dimensional, large-strain, mixed porohyperelastic transport and swelling (MPHETS) finite element model was developed in MATLAB and incorporated with a well-known growth model for soft tissues to allow the model to grow (increase in length) or shrink (decrease in length) at constant material density. By using the finite element model to determine the deformation and stress state, it is possible to implement different growth laws in the program in the future to simulate how soft tissues grow and behave when exposed to various stimuli (e.g. mechanical, chemical, or electrical). The essential assumptions needed to use the MPHETS model with growth are clearly identified and explained in this paper. The primary assumption in this work, however, is that the stress upon which growth acts is the stress in the solid skeleton, i.e. the effective stress, S(eff). It is shown that significantly different amounts of growth are experienced for the same loading conditions when using a porohyperelastic model as compared to a purely solid model. In one particular example, approximately 51% less total growth occurred in the MPHETS model than in the solid model even though both problems were subjected to the same external loading. This work represents a first step in developing more sophisticated models capable of capturing the complex mechanical and biochemical environment in growing and remodeling tissues.

Glatiramer acetate treatment directly targets CD11b(+)Ly6G(-) monocytes and enhances the suppression of autoreactive T cells in experimental autoimmune encephalomyelitis.

Glatiramer acetate (GA) is used for the treatment of relapsing-remitting multiple sclerosis (MS) and can suppress experimental autoimmune encephalomyelitis in animals. Effective GA treatment is associated with the induction of anti-inflammatory T(H)2 responses and antigen-specific expansion of CD25(+)/Foxp3(+) Tregs through the modulation of antigen-presenting cells. Here, we show that intravenous injection of fluorochrome-labelled GA resulted in rapid and specific binding of GA to CD11b(+) F4/80(lo) Ly6G(-) blood monocytes via an MHC class II-independent mechanism. Intravenous GA treatment enhanced the intrinsic capability of these monocytes to directly suppress T cell proliferation in vitro. The suppressive function correlated with reduced proliferation of myelin-specific T cells in vivo after intravenous GA treatment. In contrast, subcutaneous treatment with GA inhibited the pro-inflammatory IFNγ-producing T cell phenotype rather than suppressing T cell proliferation. These data indicate that (1) GA engages directly with circulating monocytes to induce type II monocyte suppressor function; and (2) the therapeutic efficacy of GA may be expanded by employing different routes of GA administration to engage alternative mechanisms of suppression of autoreactive T cells in MS.

Polymeric endoaortic paving: Mechanical, thermoforming, and degradation properties of polycaprolactone/polyurethane blends for cardiovascular applications.

Polymeric endoaortic paving (PEAP) is a process by which a polymer is endovascularly delivered and thermoformed to coat or "pave" the lumen of the aorta. This method may offer an improvement to conventional endoaortic therapy in allowing conformal graft application with reduced risk of endoleak and customization to complex patient geometries. Polycaprolactone (PCL)/polyurethane (PU) blends of various blend ratios were assessed as a potential material for PEAP by characterizing their mechanical, thermoforming and degradation properties. Biaxial tension testing revealed that the blends' stiffness is similar to that of aortic tissue, is higher for blends with more PCL content, and may be affected by thermoforming and degradation. Tubes of blends were able to maintain a higher diameter increase after thermoforming at higher PCL content and higher heating temperatures; 50/50 blend tubes heated to 55 °C were able to maintain 90% of the diameter increase applied. Delamination forces of the blends ranged from 41 to 235 N m⁻². In a Pseudomonas lipase solution, the 50/50 blend had a 94% lower degradation rate than pure PCL, and the 10/90 blend exhibited no degradation. These results indicate that PEAP, consisting of a PCL/PU blend, may be useful in developing the next generation of endoaortic therapy.

Colchicine suppresses neutrophil superoxide production in a murine model of gouty arthritis: a rationale for use of low-dose colchicine.

BACKGROUND AND PURPOSE: When used to treat gouty arthritis, colchicine is believed to work by inhibiting microtubule-dependent cell infiltration. However, in vitro, colchicine also reduces monosodium urate (MSU)-induced superoxide production by neutrophils. Our study aimed to compare the effects of colchicine on neutrophil superoxide production and infiltration in an in vivo model of acute gouty inflammation. EXPERIMENTAL APPROACH: In vitro: Human and murine peritoneal neutrophils were incubated with MSU with and without colchicine, and superoxide production was measured. In vivo: Mice were treated with colchicine followed by an intraperitoneal injection of MSU to induce acute inflammation. After 4h, the peritoneal cells were recovered to measure superoxide production and neutrophil infiltration. Sera were tested for liver and renal toxicity. KEY RESULTS: Colchicine dose-dependently inhibited MSU-induced superoxide production by both human and murine neutrophils in vitro. Oral colchicine inhibited MSU-induced superoxide production by neutrophils in vivo at doses 100 times lower than those required to inhibit neutrophil infiltration and without acute liver or renal toxicity. Neutrophils treated with colchicine in vivo still produced superoxide in response to another stimulus, 4-beta-phorbol-12-myristate-13-acetate. CONCLUSIONS AND IMPLICATIONS: These results show a beneficial effect of colchicine for the treatment of MSU-induced superoxide production in vivo at sub-toxic doses without compromising superoxide production by other physiological processes. This is the first in vivo data to provide a biological rationale that supports the implementation of low dose, non-toxic, colchicine therapy for the treatment of gouty arthritis.

Effect of calmidazolium analogs on calcium influx in HL-60 cells.

The structure-activity relationships of calmidazolium analogs with respect to intracellular calcium levels were investigated in HL-60 cells. Quaternized derivatives of miconazole and clotrimazole, known inhibitors of store-operated calcium (SOC) channels, were synthesized. The quaternary N-methyl derivatives of miconazole (3) and clotrimazole (6) had no effect on intracellular calcium levels, alone or after elevation of calcium induced by ATP. Calmidazolium alone induced a large increase in intracellular calcium levels in HL-60 cells (EC(50) 3 microM). Similar effects were observed for miconazole derivatives 1 (EC(50) 15 microM) and 2 (EC(50) 10 microM), wherein the diphenylmethyl group in calmidazolium was replaced by a 3,5-difluorobenzyl or cyclohexylmethyl group, respectively. The analogous clotrimazole derivatives 4 and 5 had no effect on intracellular calcium levels. The elevation of calcium levels by calmidazolium, 1, and 2 appears to be comprised of a calcium release component from inositol trisphosphate (IP(3))-sensitive stores followed by a large calcium influx component. Calcium influx was greater than that normally observed due to depletion of IP(3)-sensitive calcium stores and activation of SOC channels. In addition, only a small component of the calmidazolium-elicited influx was inhibited by the SOC channel blocker miconazole. Thus, certain quaternized imidazoles substituted with large residues at both nitrogens of the imidazole ring caused both release and influx of calcium, the latter in part through SOC channels but mainly through an undefined cationic channel. Quaternized imidazoles, unlike the parent nonquaternary imidazole miconazole, did not block SOC channels. Inhibitory effects on calmodulin-activated phosphodiesterase did not correlate with effects on calcium release and influx.

Store-operated calcium channels in HL-60 cells effects of temperature, differentiation and loperamide.

The effect of temperature on calcium release and influx has been compared in differentiated and undifferentiated HL-60 cells. Receptor-mediated release of intracellular calcium by ATP was little affected by temperature in HL-60 cells. In differentiated HL-60 cells the store-operated calcium (SOC) channel-dependent sustained elevation of calcium levels after ATP was maximal at 25-29 degrees C; at higher temperatures calcium levels returned relatively rapidly towards basal levels. In undifferentiated cells, a SOC channel-dependent sustained elevation of calcium levels was not observed with levels returning to basal levels much more rapidly than in differentiated cells. The initial thapsigargin-initiated elevation of calcium did not become maximal until about 25 degrees C in both differentiated and undifferentiated HL-60 cells. In differentiated cells, the SOC channel-dependent sustained elevation of calcium after thapsigargin was maximal at 30-37 degrees C, while in undifferentiated cells, the sustained elevation was maximal at 25-30 degrees C. Loperamide, which augments the SOC channel-dependent sustained elevation of calcium, showed a temperature-dependent response that was maximal at about 22 degrees C after either ATP or thapsigargin and was minimal at 37 degrees C. In contrast, inhibition of SOC channel-dependent elevation of calcium by miconazole or trifluoperazine was not greatly affected by temperature.

Pediatric clerkship experience and performance in the Nebraska Education Consortium: a community vs university comparison.

OBJECTIVE: To compare the reported experiences and performance on end-of-course examinations of students completing their pediatric clerkship at the University of Nebraska Medical Center (UNMC), Omaha, with that of students completing their clerkship in a community pediatrician's practice (CPP) outside the Omaha metropolitan area. DESIGN: Cohort study. SETTING: Private and/or institutional practices with both ambulatory and hospital components. PARTICIPANTS: For the academic year 1996-1997, all 113 students completing the 8-week third-year pediatric clerkship returned a questionnaire detailing their opinions of the experience. They also completed written (multiple-choice and essay questions) and oral (standardized parent interview) examinations, locally prepared and based on clerkship curriculum objectives provided to the students at orientation. Prior to student placement in the CPP, the clerkship goals, content, and evaluation methods as well as techniques for teaching in a busy office practice were reviewed with the CPP physicians. Eighty-one students performed their clerkship at UNMC while 31 spent all but the first week of the clerkship in the CPP. MAIN OUTCOME MEASURES: The students' opinions about their experiences and their performances on the end-of-course examinations were compared. Statistical analysis of the questionnaire was done using the Fisher exact test and the Mantel-Haenszel chi2 test while examination performance was compared using the t test and the Wilcoxon rank sum test. RESULTS: The UNMC and CPP groups reported similar opinions of their experiences in the newborn nursery and the inpatient portion of the clerkship, but the CPP students were much more positive about their learning experience in the clinic (P=.001). The CPP students reported more involvement in the patient's overall care (P<.001) and in other aspects of clinic operation (P<.001). The UNMC and CPP students had similar opinions of curriculum content, reading material, and didactic instruction. No group differences were found regarding interest in pediatrics as a career. Most importantly, no group differences were found in performance on any portion of the end-of-course examinations. CONCLUSIONS: Community-based education at the third-year clerkship level can be accomplished without a significant effect on student examination performance if students and faculty are aware of and adhere to a common set of goals. The end result is a much more robust experience for students who spend the clerkship in the practice of a community-based pediatrician.

Signal transduction mechanisms involved in angiotensin-(1-7)-stimulated arachidonic acid release and prostanoid synthesis in rabbit aortic smooth muscle cells.

This study investigated the signal transduction mechanisms of angiotensin-(1-7) [Ang-(1-7)]- and Ang II-stimulated arachidonic acid (AA) release for prostaglandin (PG) production in rabbit aortic vascular smooth muscle cells. Ang II and Ang-(1-7) enhanced AA release in cells prelabeled with [3H]AA. However, 6-keto-PGF1 alpha synthesis produced by Ang II was much less than that caused by Ang-(1-7). In the presence of the lipoxygenase inhibitor baicalein, Ang II enhanced production of 6-keto-PGF1 alpha to a greater degree than Ang-(1-7). Angiotensin type (AT)1 receptor antagonist DUP-753 inhibited only Ang II-induced [3H]AA release, whereas the AT2 receptor antagonist PD-123319 inhibited both Ang II- and Ang-(1-7)-induced [3H]AA release. Ang-(1-7), receptor antagonist D-Ala7-Ang-(1-7) inhibited the effect of Ang-(1-7), but not of Ang II. In cells transiently transfected with cytosolic phospholipase A2 (cPLA2), mitogen-activated protein (MAP) kinase or Ca(++)-/cal-modulin-dependent protein (CAM) kinase II antisense oligonucleotides, Ang-(1-7)- and Ang II-induced [3H]AA release was attenuated. The CaM kinase II inhibitor KN-93 and the MAP kinase kinase inhibitor PD-98059 attenuated both Ang-(1-7)- and Ang II-induced cPLA2 activity and [3H]AA release. Ang-(1-7) and Ang II also increased CaM kinase II and MAP kinase activities. Although KN-93 attenuated MAP kinase activity, PD-98059 did not affect CaM kinase II activity. Both Ang II and Ang-(1-7) caused translocation of cytosolic PLA2 to the nuclear envelope. These data show that Ang-(1-7) and Ang II stimulate AA release and prostacyclin synthesis via activation of distinct types of AT receptors. Both peptides appear to stimulate CaM kinase II, which in turn, via MAP kinase activation, enhances cPLA2 activity and release of AA for PG synthesis.

Allogeneic bone marrow transplantation for children with acute leukemia: long-term follow-up of patients prepared with high-dose cytosine arabinoside and fractionated total body irradiation.

High-dose therapy and allogeneic matched sibling bone marrow transplantation (BMT) is considered to be the treatment of choice for children with relapsed acute lymphoblastic leukemia (ALL), or for children with acute myeloid leukemia (AML) in first remission. However, the rate of bone marrow relapse after transplant for either of these diseases remains high. In this study, we assessed the efficacy and toxicity of high-dose cytosine arabinoside and total body irradiation (TBI) followed by allogeneic BMT, for children with acute leukemia or myelodysplastic syndrome (MDS). Sixty-five pediatric patients underwent allogeneic related (n = 57) or unrelated (n = 8) BMT. Twenty-seven were transplanted for ALL in second remission (CR2), and 16 for AML in first remission (CR1). The other 22 were high risk patients: six were transplanted for ALL in third remission (CR3), two for AML in CR2, two for myelodysplastic syndrome (MDS) and 12 for acute leukemia in relapse. Patients were prepared with cytosine arabinoside 3000 mg/m2 per dose twice daily for 6 days followed by 12000 cGy TBI as 200 cGy fractions twice daily for 3 days. Minimum follow-up is 21 months. Five-year event-free survival (EFS) and the actuarial relapse rate is 59 and 14% for patients with ALL in second remission, and 38 and 14+% for patients with AML in first remission. Twelve patients have relapsed (three are alive in remission after testicular or marrow relapse) and 28 have died of other causes. Acute GVHD with or without infection was the cause of death in 11 patients. Ten of the 11 patients who died of acute GVHD were considered at 'high risk' for GVHD (inadequate GVHD prophylaxis, or mismatched family donor or a matched unrelated donor). Toxicities in the immediate post-BMT period included diarrhea, oropharyngeal mucositis and conjunctivitis. Significant late toxicities included short stature, avascular necrosis of bone, and poor school performance (most often in patients who had received prior cranial irradiation). Our conclusions are that high-dose Ara-C and TBI followed by allogeneic bone marrow transplantation is effective therapy for children in second complete remission of their acute leukemia. However, significant late toxicities occur, and it is clear that more effective, less toxic therapies are necessary for these patients.

Cytodifferentiation of a Wilms' tumor pulmonary metastasis: theoretic and clinical implications.

BACKGROUND: Complete maturation (cytodifferentiation) of treated metastatic Wilms' tumor is an infrequent occurrence. In a large series of reports, Wilms' metastases have generally contained malignant blastemic elements admixed with lesser amounts of cytodifferentiated mesenchyme. The authors describe a patient in whom complete maturation of a pulmonary metastasis was documented after intensive chemoradiotherapy. METHODS: A MEDLINE search was employed to identify pertinent cases from 1966 to the present. Key words used in the search included Wilms' tumor, relapse, therapy, metastasis, maturation, and cytodifferentiation. Four patients were identified as having completely mature cytodifferentiated pulmonary metastases of Wilms' tumor after chemotherapy; one had also undergone irradiation of the pulmonary metastasis. RESULTS: The primary tumor was an extremely necrotic blastemic Wilms' tumor devoid of maturation, as studied after irradiation and chemotherapy. The lung metastases (examined 13 years later) were represented by a scar and a nodule comprised of bland epithelium and tubules admixed with mature smooth muscle. Immunohistochemical stains, used to assess the proliferative rate of these cells, revealed a nearly negligible proliferation index. CONCLUSIONS: This report suggests that therapy (chemotherapy and/or irradiation) may effect, on occasion, complete cytodifferentiation of Wilms' tumor pulmonary metastasis. Although this would appear to be an uncommon event, its true incidence is unknown, because few patients with metastatic pulmonary Wilms' tumor are subjected to biopsy. The findings of this study suggest that for children with radiologically stable Wilms' lung metastases (as determined by imaging studies) who are yet undergoing intensive chemoradiotherapy, the notion of a surgical biopsy should be entertained to determine the true nature of the radiologic images. For some, this might result in the cessation of further therapy that would be unnecessary and not without complications.

Loperamide: a positive modulator for store-operated calcium channels?

The depletion of inositol trisphosphate-sensitive intracellular pools of calcium causes activation of store-operated calcium (SOC) channels. Loperamide at 10-30 microM has no effect on intracellular calcium levels alone, but augments calcium levels in cultured cells when SOC channels have been activated. In HL-60 leukemic cells, the apparent positive modulatory effect of loperamide on SOC channels occurs when these channels have been activated after ATP, thapsigargin, or ionomycin-elicited depletion of calcium from intracellular storage sites. Loperamide has no effect when levels of intracellular calcium are elevated through a mechanism not involving SOC channels by using sphingosine. Loperamide caused augmentation of intracellular calcium levels after activation of SOC channels in NIH 3T3 fibroblasts, astrocytoma 1321N cells, smooth muscle DDT-MF2 cells, RBL-2H3 mast cells, and pituitary GH4C1 cells. Only in astrocytoma cells did loperamide cause an elevation in intracellular calcium in the absence of activation of SOC channels. The augmentation of intracellular calcium elicited by loperamide in cultured cells was dependent on extracellular calcium and was somewhat resistant to agents (SKF 96365, miconazole, clotrimazole, nitrendipine, and trifluoperazine) that in the absence of loperamide effectively blocked SOC channels. It appears that loperamide augments influx of calcium through activated SOC channels.

Mortality associated with cervicofacial necrotizing fasciitis.

Cervicofacial necrotizing fasciitis is a rare infection but still occurs and carries a mortality rate up to 60%. It is a polymicrobial infection that is characterized by diffuse necrosis of fascial planes and subcutaneous tissues. Diagnosing early stages of cervicofacial necrotizing fasciitis in relationship to other soft tissue infections of odontogenic origin is difficult and leads to less aggressive treatment with resulting increased morbidity and mortality. To prevent this significant mortality and morbidity associated with cervicofacial necrotizing fasciitis early presentation, recognition and treatment by health care provider is essential.

Treatment of veno-occlusive disease of the liver with bolus tissue plasminogen activator and continuous infusion antithrombin III concentrate.

Veno-occlusive disease (VOD) of the liver is a common complication of BMT and is accompanied by reduced levels of natural anticoagulants and by multi-organ dysfunction. We describe two cases of clinical VOD developing after autologous BMT and accompanied by ultrasonographic features of reversed portal venous flow. In both cases the patients had decreased levels of antithrombin (AT). Once the diagnosis of VOD was made, these patients were treated with tissue plasminogen activator (tPA) and continuous infusion AT. Each patient had radiographic and clinical resolution of VOD with the therapy. This novel treatment appears to have reversed the course of VOD without the increased risk of bleeding seen in the use of heparin therapy.

A prospective study of the efficacy of various gloving techniques in the application of Erich arch bars.

PURPOSE: This is a prospective study of the efficacy of three different techniques of triple gloving during the application of Erich arch bars. Two different cut-resistant glove liners and three layers of latex gloves were compared with double gloving. METHODS AND MATERIALS: Thirty patients underwent Erich arch bar placement from first molar bilaterally on both arches. Two surgeons per case were arbitrarily placed into one of four groups that included double latex gloving, triple gloving with kevlar or stainless steel glove liners, or triple layer latex gloving, based on the availability of glove liners. All gloves were collected postoperatively and tested for perforation using water insufflation. RESULTS: One hundred eight of 120 outer gloves were perforated. There were 16 perforations in 11 inner gloves of the double latex glove group, but no perforations in the inner gloves of the triple latex glove group. There were two inner gloves with one perforation each in the stainless steel group and one glove with a perforation in the kevlar group. All techniques of triple gloving were found to be superior to double gloving. There was no difference between the techniques of triple gloving. CONCLUSION: During certain high-risk procedures greater protection to the surgeon can be obtained by triple gloving. The use of cut-resistant glove liners or triple layer latex gloving is superior to double layer latex gloving.

Induction of immune tolerance in a 7-year-old hemophiliac with an anaphylactoid inhibitor.

BACKGROUND: Anaphylactic reactions were a rare complication of low purity VIII concentrates, but not with high purity VIII concentrates. CASE: 7 y/o WM with severe hemophilia A, received only cryoprecipitate and monoclonally purified VIII concentrates; developed post-infusional urticaria. A 2-Bethesda-unit inhibitor was detected. Generalized urticaria and bronchospasm following factor developed as the titer increased. Skin tests demonstrated reactivity to plasma derived VIII, but not recombinant VIII (rhVIII). Attempts at desensitization using rhVIII failed. ELISA revealed an anti-VIII IgE antibody. He was treated with a modified tolerance regimen using rhVIII starting at 500 U/day with aggressive premedication. The dosage increased by 200 U weekly as tolerated to a maximum of 100 U/kg/d without symptoms. RESULTS: His antibody titer decreased rapidly once he started 100 U/kg/d. Six months later, the inhibitor was < 1 Bethesda unit. CONCLUSION: Immune tolerance induction using a graduated dosage of rhVIII was successful.

Biodiversity: measurement and estimation.

In introducing a series of 11 papers on the measurement and estimation of biodiversity, eight crucial questions are posed: What is 'biodiversity'? Is biodiversity just the number of species in an area? If biodiversity is more than the number of species how can it be measured? Are all species of equal weight? Should biodiversity measures include infraspecific genetic variance? Do some species contribute more than others to the biodiversity of an area? Are there useful indicators of areas where biodiversity is high? And can the extent of biodiversity in taxonomic groups be estimated by extrapolation? In addition, the modern concept of biological diversity is attributed to Elliot R. Norse and his colleagues.