Multivertebral Kaposiform hemangioendothelioma presenting as scoliosis - A case report and review of literature

Kaposiform hemangioendothelioma (KHE) is a rare, locally invasive vascular tumour of childhood that may occur in soft tissue or bones, and is associated with cutaneous plaques and Kasabach-Merritt phenomenon (KMP). We present an instance of a 9-year-old girl with primary vertebral involvement of KHE, whose clinical presentation was with painless, progressive scoliosis alone, sans cutaneous markers. We highlight the imaging features of this rare manifestation and importance of histopathological diagnosis for optimal management.

Gauze for concern: A Case Report and systematic review of delayed presentation of paraspinal textiloma

Textilomas, gossypibomas, muslinomas and gauzomas, otherwise collectively known as Retained Non-absorbable Hemostatic Material (RNHM), are surgical materials such as cotton or gauze pads that are accidentally retained in the surgical bed post-operatively. They may present acutely with signs of infection or may rarely remain chronic and asymptomatic; the latter posing a significant challenge to clinical and imaging diagnosis. Textilomas are not routinely reported due to their medicolegal implications and are usually encountered fortuitously. Here, we report a case of an individual who presented with a non-specific lower backache, had a remote history of lumbar discectomy and in whom a textiloma at the postoperative site was seen to mimic a soft-tissue mass on imaging. In addition, we review current, up-to-date literature on delayed presentations of such retained materials after surgery of the lumbar spine.

Case report

A 43-year-old male presented with pain in his right lower back and gluteal region. He had undergone an L4-L5 discectomy 11 years ago, remained asymptomatic since, and noticed an insidious, worsening pain a week before presentation. Mild tenderness was elicited over the region of pain. A clinical diagnosis of L4-L5 extraforaminal disc prolapse with deep surgical site infection was made. Ultrasound showed an iso-to-hyperechogenic lesion in the right lower paraspinal region. MRI showed a very well-defined, ovoid T1-hypointense and T2-iso-hypointense lesion in the deep posterior paraspinal region of the L4/5 level adjacent to right laminar process of L4 vertebra. The lesion caused scalloping and chronic erosion of the laminar process. No obvious air pockets were present. The features of infection, like soft tissue oedema and collection, were absent. Based on imaging, differentials of nerve sheath tumour and gossipybomas was made. Open wound exploration was performed, which showed a wad of gauze within the right L4-L5 interlaminar space, with thin surrounding granulation tissue. The L4-L5 disc and exiting nerve root were normal. The mass was removed, local washing was done and wound was closed.

Conclusion

Though unfortunate and relatively rare, the possibility of a textiloma must be considered among the differential diagnoses of a mass in the spinal region in the event of prior surgery, no matter how remote the history. Clinical presentation may vary, but the imaging appearance is largely consistent and can be relied upon to prevent unnecessary investigation and facilitate early surgical removal of the offending retained material.

Peek screw displacement after PCL reconstruction: A radiographic red herring solved by MRI

Posterior cruciate ligament (PCL) repair has been increasingly performed as opposed to conservative management of PCL tears, in order to protect against future osteoarthrosis and meniscal degeneration. Fixation of the graft to bone can be done with interference screws, of which those composed of a bioresorbable material such as polyetheretherketone (PEEK) are preferred, owing to their inertness, good fixation strength and superior MR imaging compatibility. However, PEEK screws (unlike titanium screws) are radiolucent, and can make accurate post-operative evaluation by radiographs challenging. This is the first reported case of loosening of PEEK screw post-PCL repair, which highlights the importance of MRI and potential pitfall of radiography in evaluating post-surgical ligament laxity.

Utilizing CT soft-tissue markers as a screening tool for acute invasive fungal sinusitis

OBJECTIVES

Acute invasive fungal sinusitis (AIFS) is a rapidly progressive disease, whose delayed identification results in poor outcomes, especially in immunocompromised individuals. A surge in of AIFS in the wake of the COVID-19 pandemic has lent additional morbidity and mortality to an already precarious clinical scenario. Early detection of AIFS in individuals who are symptomatic/ at risk can allow early therapy, enabling better patient outcomes. Our study aims to determine optimal soft-tissue markers on CT for the early detection of AIFS.

METHODS

In this case-control study, 142 patients with equal distribution of subjects were chosen based on histopathological diagnosis of AIFS; and their non-contrast CT scans were retrospectively assessed to determine the diagnostic utility of specific soft-tissue markers that would enable diagnosis of AIFS.

RESULTS

A total of nine markers with adequate sensitivity and specificity were identified, including pterygopalatine and sphenopalatine fossae, inferior orbital fissure and nasolacrimal duct involvement, premaxillary thickening, retro-antral and orbital stranding, and infratemporal muscle oedema. It was determined that the combined occurrence of any three out of nine markers was 91.5% sensitive and 95.9% specific for diagnosis of AIFS (p < 0.005).

CONCLUSION

Early, accurate detection of AIFS in predisposed individuals is possible with identification of soft-tissue markers on NECT, enabling early intervention.

ADVANCES IN KNOWLEDGE

Being the aggressive disease that it is, AIFS may be managed early if the index of suspicion is held high via CT imaging; which our diagnostic checklist aims at enabling.

Assessment of interobserver reliability and predictive values of CT semiquantitative and severity scores in COVID lung disease

Background

The coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and first reported in December 2019 at Wuhan, China, has since then progressed into an ongoing global pandemic. The primary organ targeted by the virus is the pulmonary system, leading to interstitial pneumonia and subsequent oxygen dependency and morbidity. Computed tomography (CT) has been used by various centers as an imaging modality for the assessment of severity of lung involvement in individuals. Two popular systems of scoring lung involvement on CT are CT semiquantitative score (SQ) and CT severity score (CT-SS), both of which assess extent of pulmonary involvement by interstitial pneumonia and are partly based upon subjective evaluation. Our cross-sectional observational study aims to assess the interobserver reliability of these scores, as well as to assess the statistical correlation between the respective CT scores to severity of clinical outcome.

Results

Both the SQ and CT-SS scores showed an excellent interobserver reliability (ICC 0.91 and 0.93, respectively, p < 0.05). The CT-SS was marginally more sensitive (99.2%) in detecting severe COVID pneumonia than SQ (86.5%). The positive predictive value of SQ (98.3%) is more than CT-SS (78%) for detecting severe disease. The similarity of interobserver reliability obtained for both scores reiterates the respective cutoff CT scores proposed by the above systems, as 18 for SQ and 19.5 for CT-SS.

Conclusion

Both the SQ and CT-SS scores display excellent interobserver reliability. The CT-SS was more sensitive in detecting severe COVID pneumonia and may thus be preferred over the SQ as an initial radiological tool in predicting severity of infection.

Among the fibers: A multimodality imaging review of intramuscular mass lesions

The common presentations of patient complaints regarding the musculoskeletal system, such as pain, swelling, and restriction of movement, lead to the imaging discovery of various lesions often located in, or arising from, skeletal muscle in the region of interest. Knowledge of the patients' clinical history, laboratory parameters, and various imaging characteristics of the implicated lesions would assist the radiologist in coming to a timely, reasonably accurate conclusion about the etiology of the patient's complaints, the severity of disease, and in directing patient therapy.

A simple and inexpensive method to control oxygen concentrations within physiological and neoplastic ranges

Traditional methods for regulating oxygen concentration ([O2]) in in vitro experiments over the range found in normal and tumor tissues require the use of expensive equipment to generate controlled gas atmospheres or the purchase of a range of gas cylinders with certified O2 percentages. Here we describe a simple and inexpensive enzymatic method for generating low, precise steady-state [O2] levels that are stable for several hours. This method is particularly applicable to the in vitro study of some classes of hypoxia-targeted antitumor prodrugs and bioreductively activated agents.

1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl]hydrazine (VNP40101M): II. Role of O 6 -alkylguanine-DNA alkyltransferase in cytotoxicity

PURPOSE

VNP40101M (1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl]hydrazine) is a sulfonylhydrazine prodrug that possesses broad spectrum antitumor efficacy in murine models. VNP40101M activation generates chloroethylating species that alkylate DNA at the O(6)-position of guanine, and a carbamoylating agent, methyl isocyanate, which inhibits O(6)-alkylguanine-DNA alkyltransferase (AGT) in model systems. We determined whether expression of AGT in Chinese hamster ovary (CHO) cells decreased sensitivity to VNP40101M and explored the mechanism of VNP40101M cytotoxicity by employing analogs of VNP40101M that generate reactive intermediates with either carbamoylating or chloroethylating activity.

METHODS

AGT was overexpressed in CHO cells by transfection with an expression vector containing the human AGT gene. Cell lines expressing AGT were employed in clonogenic assays to determine the cytotoxicity of VNP40101M and its analogs.

RESULTS

VNP40101M was more active against AGT-expressing CHO cells than 90CE (1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine), a chloroethylating generator devoid of carbamoylating activity. Furthermore, the greater the degree of AGT expression the more resistance to VNP40101M cytotoxicity. Combination chemotherapy experiments support the conclusions that methyl isocyanate and the chloroethylating species generated from the activation of VNP40101M function synergistically to kill cells.

CONCLUSIONS

The findings support the concept that alkylation of the O(6)-position of guanine residues in DNA is the predominant lesion created by VNP40101M, and that methyl isocyanate resulting from the base-catalyzed activation of VNP40101M inhibits AGT and presumably other enzymes involved in DNA repair, thereby enhancing the yield of the DNA G-C interstrand crosslinks responsible for the antitumor activity of this agent.

1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl]hydrazine (VNP40101M): I. Direct inhibition of O 6 -alkylguanine-DNA alkyltransferase (AGT) by electrophilic species generated by decomposition

PURPOSE

To investigate the interaction of the electrophilic species generated by the decomposition of the antineoplastic prodrug 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl]hydrazine (VNP40101M) on the ability of O(6)-alkylguanine-DNA alkyltransferase (AGT) to repair alkylated O(6)-chloroethylguanine and/or N(1),O(6)-ethanoguanine DNA lesions.

MATERIALS AND METHODS

The contributions of inhibitory electrophilic species generated from VNP40101M towards AGT was assessed using analogues that selectively generated either the chloroethylating or the carbamoylating components of VNP40101M. The activity of AGT was determined from the inhibition of crosslink formation from O(6)-chloroethylguanine and/or N(1),O(6)-ethanoguanine lesions. The half-lives of sulfonylhydrazine derivatives and isocyanates were measured using an acidification assay which gives a change in absorbance proportional to the release or consumption of small quantities of protons.

RESULTS

Both of the reactive components produced by VNP40101M directly inactivated cloned human AGT; the carbamoylating moiety (IC(50) about 13 micro M) was approximately seven- to eight-fold more potent than the alkylating component(s) (IC(50) about 100 micro M). These inhibitory actions were moderated by the addition of naked T5 bacteriophage DNA. Thus, AGT bound to DNA was markedly more resistant than free AGT to these electrophilic species. DNA also blocked the spontaneous loss of AGT activity which occurred upon incubation of this protein under mild conditions.

CONCLUSIONS

The reaction of AGT with the methyl isocyanate generated from the decomposition of VNP40101M increased the net number of crosslinks generated by VNP40101M compared to a sulfonylhydrazine prodrug that formed the equivalent alkylating species in the absence of the cogeneration of methyl isocyanate. These actions may be of significance to the antineoplastic activity of VNP40101M.

Inhibition of DNA cross-linking by mitomycin C by peroxidase-mediated oxidation of mitomycin C hydroquinone

Mitomycin C requires reductive activation to cross-link DNA and express anticancer activity. Reduction of mitomycin C (40 microm) by sodium borohydride (200 microm) in 20 mm Tris-HCl, 1 mm EDTA at 37 degrees C, pH 7.4, gives a 50-60% yield of the reactive intermediate mitomycin C hydroquinone. The hydroquinone decays with first order kinetics or pseudo first order kinetics with a t(12) of approximately 15 s under these conditions. The cross-linking of T7 DNA in this system followed matching kinetics, with the conversion of mitomycin C hydroquinone to leuco-aziridinomitosene appearing to be the rate-determining step. Several peroxidases were found to oxidize mitomycin C hydroquinone to mitomycin C and to block DNA cross-linking to various degrees. Concentrations of the various peroxidases that largely blocked DNA cross-linking, regenerated 10-70% mitomycin C from the reduced material. Thus, significant quantities of products other than mitomycin C were produced by the peroxidase-mediated oxidation of mitomycin C hydroquinone or products derived therefrom. Variations in the sensitivity of cells to mitomycin C have been attributed to differing levels of activating enzymes, export pumps, and DNA repair. Mitomycin C hydroquinone-oxidizing enzymes give rise to a new mechanism by which oxic/hypoxic toxicity differentials and resistance can occur.

Structure-activity studies of novobiocin analogs as modulators of the cytotoxicity of etoposide (VP-16)

We have previously reported that the antibiotic novobiocin enhanced the toxicity of the anticancer agent etoposide (VP-16) to several drug-sensitive and -resistant tumor cell lines. The increase in VP-16 cytotoxicity produced by novobiocin was not due to the combined effects of these agents on topoisomerase II, but to inhibition by novobiocin of VP-16 efflux, which in turn led to increased accumulation of VP-16 and increased formation of potentially lethal VP-16-stabilized topoisomerase II-DNA covalent complexes. We have now identified novobiocin analogs that are essentially equivalent to novobiocin as inhibitors of the activity of topoisomerase II, but that are more potent than novobiocin (a) as modulators of the cytotoxicity of VP-16 to WEHI-3B leukemia and A549 lung carcinoma cells and (b) in increasing VP-16 accumulation in these cell lines. Thus, removal of the sugar moiety of novobiocin to form novobiocic acid enhanced the potency of the antibiotic as a modulator of VP-16, whereas the substituted coumarin ring alone (U-7587) was devoid of VP-16 modulatory activity. Modifications of the side chain of novobiocin significantly influenced modulatory activity, with cyclonovobiocic acid, which was formed from novobiocic acid by acid-catalyzed cycloaddition, being the most active in enhancing the cytotoxicity of VP-16. The increased potency of novobiocic acid and cyclonovobiocic acid as modulators of VP-16 activity was achieved with no change from novobiocin in the capacity of these analogs to inhibit the catalytic activity of mammalian topoisomerase II, indicating a change in the specificity of these analogs.

1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)-2-(methylamino)carbonylhydrazine (101M): a novel sulfonylhydrazine prodrug with broad-spectrum antineoplastic activity

Our laboratory has synthesized and evaluated the anticancer activity of a number of sulfonylhydrazine DNA modifying agents. As a class, these compounds possess broad spectrum antitumor activity, demonstrating significant activity against a variety of experimental murine tumors, including the P388 and L1210 leukemias, B16 melanoma, M109 lung carcinoma, and M5076 reticulum cell sarcoma, as well as against the human LX-1 lung carcinoma xenograft. The current report describes the activity of a more recently synthesized member of this class, 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-(methylamino)carbonylhydrazine (101M). 101M was active in mice against the i.p. implanted L1210 leukemia over a wide range of doses and produced long-term survivors when administered as a single i.p. bolus of 10, 20, 40, 60, or 80 mg/kg, demonstrating a wider margin of safety than the nitrosourea, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Curative therapy was achieved with doses of 101M that did not produce depression of the bone marrow. 101M was also highly effective against the L1210 leukemia when administered by the oral route. The ability of 101M to penetrate the blood-brain barrier and eradicate leukemia cells in the brain was remarkable (>6 log kill). This agent was also curative against L1210 variants resistant to cyclophosphamide, BCNU, or melphalan. Mice implanted with the murine C26 colon carcinoma were also cured by two injections of 10 or 20 mg/kg of 101M. Administration of 101M by two different well-tolerated regimens caused complete regression of established human glioblastoma U251 xenografts in 100% of treated mice, and significant responses were also obtained with 101M against advanced murine M109 lung carcinomas in mice. The broad spectrum of anticancer activity of the sulfonylhydrazine prodrug 101M coupled with the wide range of therapeutic safety exhibited by this agent, makes 101M particularly attractive for further development and clinical evaluation.

Comparison of DNA lesions produced by tumor-inhibitory 1,2-bis(sulfonyl)hydrazines and chloroethylnitrosoureas

1,2-Bis(sulfonyl)hydrazine derivatives, designed to generate several of the electrophilic species classically believed to be responsible for the alkylating (chloroethylating) and/or carbamoylating activities of the chloroethylnitrosoureas (CNUs), were compared with respect to the cross-linking and nicking of T7 DNA to that caused by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and 1-(2-chloroethyl)-3-(4-trans-methylcyclohexyl)-1-nitrosourea (MeCCNU). In the case of BCNU, a large proportion of T7 DNA strand nicking was found to be due to the generation of 2-chloroethylamine, produced from the hydrolysis of 2-chloroethylisocyanate, in turn formed during the decomposition of the parental nitrosourea. 1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (compound 1) gave a greater yield of DNA cross-links than the CNUs. Compound 1, as well as its derivatives that were incapable of generating 2-chloroethylisocyanate, did not produce detectable levels of strand nicking, indicating that N7-alkylation of guanine did not occur to a significant extent with these agents. Since compound 1 and its derivatives are believed to generate chloronium and chloroethyldiazonium ions, it would appear that these species could not be significantly involved in the N7-alkylation of guanine caused by the CNUs. The relatively low level of N7-alkylation of guanine residues and the relatively high yield of cross-links generated by some of the 1,2-bis(sulfonyl)-1-(2-chloroethyl)hydrazine derivatives implies that they are more exclusive O6-guanine chloroethylating agents than the CNUs. O6-Guanine chloroethylation is believed to be the therapeutically relevant event produced by the CNUs; therefore, compound 1 derivatives represent promising new cancer chemotherapeutic agents, since they appear to generate lower quantities of therapeutically unimportant, yet carcinogenic lesions, and more of the therapeutically relevant O6-guanine chloroethylation than the CNUs.

Hypoxia-selective nitrobenzyloxycarbonyl derivatives of 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazines

Some 4- and 2-(nitrobenzyloxycarbonyl)-1, 2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazines (4, 6, and 7) were synthesized and evaluated for their ability to exert preferential toxicity to hypoxic EMT6 mammary carcinoma cells using a colony-forming assay. Of these, the 4,5-dimethoxy-2-nitro analogue 6 (50 microM, 1-h exposure) caused greater than 3 logs of kill of hypoxic cells, with relatively minor toxicity to corresponding aerobic cells. The ability of 4-nitro (4) and 4,5-dimethoxy-2-nitro (6) analogues to reach and kill hypoxic cells of solid tumors was also demonstrated using intradermally implanted EMT6 solid tumors in mice. In addition, a possible source of toxicity to normal tissue, i. e., the activation of the 4-nitrobenzyl derivative 4 by glutathione S-transferase-catalyzed thiolysis, was essentially eliminated by replacing one of the benzylic methylene protons by a methyl group. The 4-nitro (4) and 4,5-dimethoxy-2-nitro (6) analogues also appear to be reduced more easily under acidic conditions (pH 6.0) than under neutral conditions, as measured by differential pulse polarography. Since the pH in hypoxic regions is often lower than that in adjacent aerobic regions, this property should aid in the cytotoxic action of these agents against hypoxic cells of solid tumors.

Induction of the differentiation of HL-60 promyelocytic leukemia cells by curcumin in combination with low levels of vitamin D3

Previous studies have shown that an antisense phosphorothioate oligonucleotide to the Rel A subunit of NF- kappa B, as well as vitamin E and related antioxidants, significantly enhanced the differentiation of HL-60 leukemia cells when combined with low levels of 1 alpha, 25-dihydroxyvitamin D3 (vitamin D3) an effect accompanied by a marked inhibition of the transcription factor, NF-kappa B. Curcumin, a potent inhibitor of tumor promotion and of tumor cell growth, has also been shown to have antioxidant properties and to inhibit NF-kappa b. to ascertain whether curcumin would also enhance the differentiation of HL-60 leukemia cells produced by vitamin D3, presumably by interfering with NF- kappa B activity, the effects of curcumin on the differentiation of HL-60 cells produced by low levels of vitamin D3 were measured. Curcumin used alone did not produce a significant degree of differentiation of HL-60 cells; however, this agent markedly enhanced the expression of differentiation markers induced by low levels of vitamin D3. Curcumin also increased the differentiation of HL-60 cells when combined with vitamin D analogues (1,25-dihydroxy-16-ene-23-yne vitamin D3 and 1,25-dihydroxy-16-ene vitamin D3) that share the receptor binding properties of vitamin D3, whereas as vitamin D analogue (1,25-dihydroxy-16,23-diene vitamin D3) that caused significant calcium mobilization, but was less effective than vitamin d3 in binding the receptor, did not cause the differentiation of HL-60 cells in the presence or absence of curcumin. Several dietary compounds structurally related to curcumin (i.e., caffeic acid, chlorogenic acid, and ferulic acid) did not increase the differentiation of HL-60 cells produced by vitamin D3. However, the more lipophilic ethyl of ferulic and caffeic acid were capable of inducing the differentiation of HL-60 cells, as well as enhancing the maturation produced by vitamin D3. Curcumin caused a marked reduction in NF-kappa B activity in nuclear extracts of HL-60 cells exposed to this agent in the presence or absence of vitamin D3, supporting the possibility that NF-kappa B may be a factor in the regulation of the state of differentiation of leukemia cells.

Spectrophotometric assay for processes involving changes in hydrogen ion concentration in aqueous solution

A strategy for the design of simple colorimetric assays to follow any process that involves the net generation or consumption of hydrogen ions in aqueous solutions over the pH range of 3-10 is described. This procedure relies upon the measurement of the change in absorption when a weakly or moderately buffered solution of a pH indicator is subjected to a small change in pH. Buffers and indicators are chosen with closely matching pKa values. The versatility of this type of assay technique is illustrated using three examples.

Antitumor 2-(aminocarbonyl)-1,2-bis(methylsulfonyl)-1-(2-chloroethyl)- hydrazines

Several 2-(aminocarbonyl)-1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydr azi nes were synthesized and primarily evaluated for antitumor activity against the murine L1210 leukemia. All of the compounds tested were capable of producing "cures" of mice bearing this tumor. One of the most active agents of this class, 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)- 2(-)[[2-chloroethyl)-amino]carbonyl]hydrazine, was further evaluated against a spectrum of transplanted murine and human solid tumors. Pronounced activity was found against all of the tumors including the murine B16F10 melanoma, M109 lung carcinoma, M5076 reticulum cell sarcoma, and the human LX-1 lung carcinoma. The activities observed compared favorably with those of the established antitumor drugs, cyclophosphamide, mitomycin C, and the nitrosoureas, evaluated concomitantly.

Studies on the mechanism of decomposition and structural factors affecting the aqueous stability of 1,2-bis(sulfonyl)-1-alkylhydrazines

1,2-Bis(sulfonyl)-1-alkylhydrazines are highly active experimental antineoplastic agents which decompose with first-order kinetics in neutral aqueous solutions. These agents generate approximately 2 mol of the corresponding sulfinate, 1 mol of nitrogen, and 1 mol of the appropriate alcohol, produced as a consequence of the alkylation of water. Increasing the leaving-group ability of the sulfonyl moiety on N-1 shortens the half-life, while the converse happens with N-2 substitutions. Linear Hammett relationships are found for both types of substitutions. The predictable kinetics of decomposition makes these agents potential candidates for use in regional chemotherapy, where compounds with tunable short half-lives may offer some advantage. Prodrugs of extremely short-lived derivatives of this class may also have utility as targeted alkylating agents.

Synthesis and evaluation of 1-acyl-1,2-bis(methylsulfonyl)-2-(2- chloroethyl)hydrazines as antineoplastic agents

A series of 1-acyl-1,2-bis(methylsulfonyl)-2-(2-chloroethyl)hydrazines, conceived as more potent analogs of 1-(2-chloroethyl)-1,2,2-tris(methylsulfonyl)hydrazine, were synthesized and evaluated for antineoplastic activity against the L1210 leukemia in mice. Of these, 1-acetyl-1,2-bis-(methylsulfonyl)-2-(2-chloroethyl)hydrazine produced "cures" of mice bearing the L1210 leukemia at dosage levels that were considerably less than those at which the tris(sulfonyl) analog produced its antineoplastic effects. This compound was also found to have pronounced activity against the P388 leukemia and against several solid tumors, including the B16F10 melanoma, the M5076 reticulum cell sarcoma, and the M109 lung carcinoma. Furthermore, the acyl derivatives were in general considerably more resistant to hydrolysis in aqueous media and more prone to protease- and thiol-mediated activation than the tris(sulfonyl) analog. The former property is important to formulation, while the latter properties may result in some degree of drug targeting and enhancement of the therapeutic indices of these agents.

Anticonvulsant properties of some Mannich bases of conjugated arylidene ketones

Thirty 1-aryl-5-dimethylamino-1-penten-3-one hydrohalides and related compounds were prepared as candidate anticonvulsants and evaluated in maximal electroshock seizure (MES), subcutaneous pentylenetetrazole threshold, and neurotoxicity screens. Following administration by the intraperitoneal route, many of the compounds were active in the MES screen, whereas only 10% of the Mannich bases afforded protection in the subcutaneous pentylenetetrazole test. Quantitation of half of the compounds prepared revealed that many had activity comparable with that of clinically useful drugs in the MES screen. The anticonvulsant properties of eight of the compounds following oral administration were reduced considerably or abolished compared with those following intraperitoneal administration. Various synthetic strategies for future development of potential anticonvulsants are outlined.

The effects of the methylating agent 1,2-bis(methylsulfonyl)-1-methylhydrazine on morphology, DNA content and mitochondrial function of Trypanosoma brucei subspecies

Repeated exposure of trypanosomes in vitro or in vivo to low concentrations of the methylating agent 1,2-bis(methylsulfonyl)-1-methylhydrazine induces a series of moderately synchronous morphological and biochemical changes. Cell division halts and the long-slender bloodstream forms transform to short-stumpy forms via larger intermediate-stage cells which contain approximately double the normal G2 content of DNA. In common with naturally occurring short-stumpy trypanosomes, drug-induced short-stumpy forms do not infect rodents and when transferred to Cunningham's medium, transform to and replicate as procyclics. Furthermore, these short-stumpy forms exhibit alpha-ketoglutarate supported motility and oxygen consumption, acquire the ability to reduce nitroblue tetrazolium (NADH diaphorase positivity) and appear to be in the G1 or G0 stage of the cell cycle based upon DNA content.

Synthesis and evaluation of 1,2,2-tris(sulfonyl)hydrazines as antineoplastic and trypanocidal agents

Several 1,2,2-tris(sulfonyl)hydrazines, conceived as prodrugs of 1,2-bis(sulfonyl)hydrazines, were synthesized and evaluated for antineoplastic and trypanocidal activities in mice. 1-Methyl-1,2,2-tris(methylsulfonyl)hydrazine emerged as an extremely efficacious antitrypanosomal agent, whereas 1-(2-chloroethyl)-1,2,2-tris(methylsulfonyl)hydrazine was inactive. In contrast, 1-(2-chloroethyl)-1,2,2-tris(methylsulfonyl)hydrazine displayed potent antineoplastic activity, producing several 60-day "cures" of mice bearing leukemia L1210, leukemia P388, or Sarcoma 180. Furthermore, the fact that the tris(sulfonyl) derivatives will not generate isocyanates, which contribute to the host toxicity of nitrosoureas like 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), makes them agents of significant promise in trypanosomal and cancer chemotherapy.

Methylating agents as trypanocides

Methylating agents, such as streptozotocin, procarbazine, N-methyl-N-nitrosourea, dimethyl sulfate, 1,2-dimethylhydrazine, and a series of 1,2-bis(sulfonyl)-1-methylhydrazines synthesized in this laboratory, were evaluated and shown to be therapeutically active against murine models of African trypanosomiasis. At high dose levels, methylating agents halted trypanosome proliferation and transformed cells into bizarre forms containing multiple nuclei and kinetoplasts. These cells disappeared from the bloodstream of mice bearing these organisms in 48-72 h. When administered at repetitive low doses, methylating agents induced the entire population of trypanosomes to differentiate into biochemically distinct short-stumpy forms in a synchronous manner. These results suggest that methylating agents may be used as biochemical tools in the study of trypanosome differentiation.

Cytotoxic and DNA-damaging effects of 1,2-bis(sulfonyl)hydrazines on human cells of the Mer+ and Mer- phenotype

A series of 1,2-bis(sulfonyl)hydrazines with the capacity to function as alkylating agents have been evaluated for their toxicity towards Mer- HT29 and Mer- BE cells, and for their ability to produce DNA damage expressed as single-strand breaks and DNA interstrand cross-links. Compounds of this class with methylating potential showed a marked difference in their capacity to inhibit the growth of Mer- and Mer+ cells, being considerably more toxic to BE Mer- cells. Dose-dependent DNA single-strand breaks were induced by these agents, with the quantity of breaks produced in Mer- and Mer+ cells being essentially the same. Maintenance of these lesions did not appear to explain the differential in toxicity to BE and HT29 cells. A chloroethylating compound of this class was also more toxic to Mer- BE cells than to Mer+ HT29 cells, but the differential toxicity was considerably less than that of the methylating agents of the series. The chloroethylating agent did not produce measurable single-strand breaks of the DNA of treated cells, but caused more DNA interstrand cross-links in Mer- cells than in Mer+ cells. Thus, DNA interstrand cross-links may be at least in part responsible for the cell kill produced by this agent. The findings suggest that methylating and chloroethylating derivatives of the 1,2-bis(sulfonyl)hydrazine family have different biochemical determinants of their cytodestructive actions.

Novel 1-haloalkyl-2-nitroimidazole bioreductive alkylating agents

Solid tumors contain hypoxic cells which are relatively resistant to radiation treatment and to most forms of chemotherapy. These cells can be preferentially targeted using chemotherapeutic agents that are specifically activated by cellular reductase enzymes in the absence of oxygen. A new class of bioreductive alkylating agents based on the 2-nitroimidazole nucleus has been developed which contains a haloalkyl substituent on the N-1 position of the imidazole ring. Compounds of this series were readily reduced by mammalian NADPH-cytochrome c reductase, and reduction led to the production of an electrophilic center. This reactive component was hypothesized to be responsible for the preferential cytotoxicity of the agents of this class to hypoxic tumor cells through alkylation of cellular components.

1,2-Bis(sulfonyl)hydrazines. 3. Effects of structural modification on antineoplastic activity

A series of 1,2-bis(sulfonyl)hydrazines was synthesized and evaluated for antineoplastic activity against the L1210 leukemia and the B16 melanoma. The most active agent to emerge from this study, 1,2-bis(methylsulfonyl)-1-methylhydrazine, produced a maximum % T/C for mice bearing the L1210 leukemia or the B16 melanoma of 340% and 278%, respectively. Two N-chloroethyl analogues, conceived as bifunctional alkylating agents, were also synthesized and evaluated for antineoplastic activity against the L1210 leukemia and the B16 melanoma. Although such a modification resulted in retention of antineoplastic activity against both tumor cell lines, it did not result in enhanced antineoplastic activity.

Synthesis and evaluation of 1-(arylsulfonyl)-2-[(methoxycarbonyl)sulfenyl]-1-methylhydrazines++ + as antineoplastic agents

1-(Arylsulfonyl)-2-[(methoxycarbonyl)sulfenyl]-1-methylhydrazines, with the potential to function as biological methylating agents, were synthesized and evaluated as antineoplastic agents against the L1210 leukemia and the B16 melanoma in mice. All of the compounds of this class had significant activity against the B16 melanoma, with the most active compound, 2-[(methoxycarbonyl)sulfenyl]-1-methyl-1-[(4- methylphenyl)sulfonyl]hydrazine, producing percent T/C values for B16 melanoma tumor bearing mice of between 182 and 232 at dosage levels of from 12.5 to 50 mg/kg daily for 6 consecutive days. In contrast to the related class of agents, the N,N'-bis(sulfonyl)hydrazines reported earlier by this laboratory,1 the 1-(arylsulfonyl)-2-[(methoxycarbonyl)sulfenyl]-1-methylhydrazines were found to be inactive against the L1210 leukemia in vivo.

Synthesis and evaluation of 2-substituted 1-methyl-1-(4-tolylsulfonyl)hydrazines as antineoplastic agents

Several N-2 substituted 1-methyl-1-(4-tolylsulfonyl)hydrazines were synthesized and evaluated for antineoplastic activity against the L1210 leukemia and the B16 melanoma. The most active compound to emerge from this study, 2-(methylsulfonyl)-1-methyl-1-(4-tolylsulfonyl)hydrazine, produced maximum percent T/C values with L1210 leukemia and B16 melanoma tumor bearing mice of 207 and 209, respectively. While the attachment of an aryl-, aralkyl-, or alkylsulfonyl moiety to N-2 resulted in retention of activity against both tumor systems, the corresponding benzoyl, 4-nitrobenzoyl, and (2-nitrophenyl)sulfenyl analogues only displayed activity against the L1210 leukemia.

1,2-bis(arylsulfonyl)hydrazines. 2. The influence of arylsulfonyl and aralkylsulfonyl substituents on antitumor and alkylating activity

Several 1,2-bis(arylsulfonyl)-1-methylhydrazines were synthesized and evaluated for antineoplastic activity against the L1210 leukemia. The most active compound to emerge from this study, 2-[(4-chlorophenyl)sulfonyl]-1-methyl-1-(4-tolylsulfonyl)hydrazine , increased the survival time of tumor-bearing mice by 88%. The alkylating activity of the synthesized analogues and several compounds reported earlier was determined by measuring the absorbance at 540 nm of the alkylated product of 4-(4-nitrobenzyl)pyridine. The results obtained support the concept that the ability to alkylate is a necessary but not a sufficient condition for the expression of antitumor activity by agents of this class.

Synthesis and evaluation of N,N'-bis(arylsulfonyl)hydrazines as antineoplastic agents

Several N,N'-bis(arylsulfonyl)hydrazines, with the potential to function as biological methylating agents, were synthesized and evaluated for antineoplastic activity against the L1210 leukemia and other transplanted rodent tumors. In general, the N-methyl-N,N'-bis(arylsulfonyl)hydrazines that possess the capacity to generate an alkylating species under physiological conditions showed significant antineoplastic activity, while N,N'-bis(phenylsulfonyl)-hydrazine and N-methyl-N,N'-dibenzoylhydrazine were inactive.

Relationship between structure and antineoplastic activity of (arylsulfonyl)hydrazones of 4-pyridinecarboxaldehyde

The effects of various structural modifications on the antineoplastic activity of (arylsulfonyl)hydrazones of 4-pyridinecarboxaldehyde were examined in mice bearing either Sarcoma 180 or P388 leukemia. The introduction of different functional groups into the phenyl ring of the benzenesulfonyl moiety did not alter tumor inhibitory activity appreciably, and the pyridine ring could be replaced by 4-nitrobenzene without loss of antineoplastic activity. However, the aldehyde proton and the hydrazone proton alpha to the sulfonyl group were essential, and their substitution resulted in inactive anticancer agents.

Decomposition of 1-aryl-3-dimethylamino-1-propanone methobromides under weakly acidic conditions

Under basic conditions, some 1-aryl-3-dimethylamino-1-propanone methodbromides (2) were shown to decompose too readily to measure by the electronic absorption spectroscopy technique available. However, at pH = 5.9 and 20 degrees centigrade, the rate of deamination to the corresponding 1-aryl-2-propen-1-ones was able to be followed using Guggenheim's method and a Hammett plot showed that the rate of deamination correlated with the arly substituent constants (o). The rho value for this process was +1.00. In contrast the corresponding 1-arly-3-dimethylamino-1-propanone hybrobromides (1) did not decompose under simulated physiological conditions (pH = 7.4, 37 degrees centigrade). Neither 1 or 2 were active against P388 lymphocytic leukemia in mice but the methobromides displayed greater murine toxicity.